Organic electroluminescence device

ABSTRACT

The present invention relates to an organic electroluminescence device having high luminous efficiency (for example, external quantum efficiency) and high durability and causing little chromaticity shift after device deterioration. The present invention also relates to an organic electroluminescence device material comprising a substrate having thereon a pair of electrodes and at least one organic layer between the electrodes, the organic layer containing a light emitting layer, wherein the light emitting layer contains a metal complex having a group represented by formula (I).

TECHNICAL FIELD

The present invention relates to a luminescence device capable of converting an electric energy into light and thereby producing luminescence. More specifically, the present invention relates to an organic electroluminescence device (luminescence device or EL device).

BACKGROUND ART

An organic electroluminescence (EL) device is attracting as a promising display device because high-luminance intensity luminescence can be obtained with a low voltage. An important characteristic value of this organic electroluminescence device is a power consumption. The power consumption is represented by a product of a voltage and a current, and as the voltage value necessary for obtaining desired brightness is lower and the current value is smaller, the power consumption of the device can be more reduced.

In the production of an organic electroluminescence device, as for the method to form a thin film that is an organic layer provided between a pair of electrodes, a vapor deposition process such as vacuum deposition and a wet process such as spin coating method, printing method and an inkjet method are being performed.

Among these, when a wet process is used, an organic compound polymer whose deposition is difficult by a dry process such as vapor deposition can be used, and in the case of use for a flexible display or the like, the wet process is suitable in view of durability such as flexibility and film strength and is preferred particularly when fabricating a large-area device.

However, an organic electroluminescence device obtained by the wet process has a problem that the luminous efficiency or device durability is poor.

In recent years, the device efficiency is progressively increased by using a phosphorescent material. As for the phosphorescent material, an iridium complex, a platinum complex and the like are known (see, for example, JP-A-2001-247859 and JP-A-2007-19462), but a device satisfying both high efficiency and high durability has not yet been developed.

Also, an organic EL device where a specific phosphorescence material substituted with a specific kind of an alkyl group at a specific position with an attempt to obtain a material capable of realizing high efficiency and low voltage of a device is used as a light emitting material has been reported (see, for example, JPA-2008-210941 and US 2008-0297033). In JP-A-2008-210941, an organic EL device containing a compound having a cyclopropyl group as the substituent is described, but this is insufficient in view of luminescence quantum efficiency, drive voltage and durability, and more improvements are being demanded.

Furthermore, conventional devices sometimes cause a chromaticity shift after device deterioration, and also in this respect, improvements are being demanded.

SUMMARY OF INVENTION

An object of the present invention is to provide an organic electroluminescence device having high efficiency and high durability and causing little chromaticity shift after device deterioration. Another object of the present invention is to provide a phosphorescence material having a specific alkyl group, which is suitable for use in the device.

These objects have been attained by the following techniques.

[1]

An organic electroluminescence device including a substrate having thereon a pair of electrodes and at least one organic layer between said electrodes, the organic layer containing a light emitting layer,

wherein any one layer of the organic layer contains a metal complex having a group represented by the following formula (I).

(In formula (I), R₁ represents an alkyl group, each of R₂ and R₃ independently represents a hydrogen atom or an alkyl group, n represents an integer of 0 to 6, and Z represents a saturated 5- to 8-membered ring.) [2]

The organic electroluminescence device according to [1],

wherein in formula (I), n represents an integer of 1 to 3.

[3]

The organic electroluminescence device according to [1] or [2],

wherein in formula (I), n is 1.

[4]

The organic electroluminescence device according to any one of [1] to [3],

wherein in formula (I), each of R₂ and R₃ represents a hydrogen atom.

[5]

The organic electroluminescence device according to any one of [1] to [4],

wherein in formula (I), Z represents a cyclopentyl group or a cyclohexyl group.

[6]

The organic electroluminescence device according to any one of [1] to [5],

wherein the metal complex having a group represented by formula (I) is a metal complex represented by the following formula (1).

(In formula (1), M¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, A¹¹ represents a nitrogen atom or a carbon atom, X¹¹ represents an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom or a single bond, represents a linking group or a single bond, L¹¹ represents a partial structure having an atom bonded to X¹¹, Z¹¹ represents an aromatic nitrogen-containing heterocyclic ring, each of L¹² and L¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹¹ represents an atomic group for forming a bidentate ligand together with L¹² and L¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, S¹¹ represents a group represented by formula (I), n represents an integer of 1 to 4, and each S¹¹ may be the same as or different from every other S¹¹.) [7]

The organic electroluminescence device according to [6],

wherein the metal complex represented by formula (1) is a metal complex represented by the following formula (2).

(In formula (2), M²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of A²¹ to A²³ independently represents a nitrogen atom or a carbon atom, Z²¹ represents an aromatic nitrogen-containing heterocyclic ring, Z²² represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, each of L²² and L²³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E²¹ represents an atomic group for forming a bidentate ligand together with L²² and L²³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S²¹ and S²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S²¹ or S²² may be the same as or different from every other S²¹ or S²².) [8]

The organic electroluminescence device according to [7],

wherein the metal complex represented by formula (2) is represented by the following formula (4).

(In formula (4), M⁴¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁴³ to R⁴⁶ independently represents a hydrogen atom or a substituent, each of B⁴¹ to B⁴⁴ independently represents a nitrogen atom or C—R⁴⁷, R⁴⁷ represents a hydrogen atom or a substituent, each R⁴⁷ may be the same as or different from every other R⁴⁷, each of L⁴² and L⁴³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁴¹ represents an atomic group for forming a bidentate ligand together with L⁴² and L⁴³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁴¹ and S⁴² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁴¹ or S⁴² may be the same as or different from every other S⁴¹ or S⁴².) [9]

The organic electroluminescence device according to [8],

wherein the metal complex represented by formula (4) is represented by the following formula (5).

(In formula (5), M⁵¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁵³ to R⁵⁹ and R⁵¹⁰ independently represents a hydrogen atom or a substituent, each of L⁵² and L⁵³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁵¹ represents an atomic group for forming a bidentate ligand together with L⁵² and L⁵³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁵¹ and S⁵² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁵¹ or S⁵² may be the same as or different from every other S⁵¹ or S⁵².) [10]

The organic electroluminescence device according to [7],

wherein the metal complex represented by formula (2) is represented by the following formula (7).

(In formula (7), M⁷¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁷³ to R⁷⁶ independently represents a hydrogen atom or a substituent, each of A⁷¹ and A⁷² independently represents a nitrogen atom or a carbon atom, each of D⁷¹ to D⁷³ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D⁷¹ to D⁷³, A⁷¹ and A⁷² represents a single bond or a double bond, each of D⁷¹ to D⁷³ when these can be further substituted may have a substituent, each of L⁷² and L⁷³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁷¹ represents an atomic group for forming a bidentate ligand together with L⁷² and L⁷³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁷¹ and S⁷² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁷¹ or S⁷² may be the same as or different from every other S⁷¹ or S⁷².) [11]

The organic electroluminescence device according to [7],

wherein the metal complex represented by formula (2) is represented by the following formula (9).

(In formula (9), M⁹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁹³ and R⁹⁴ independently represents a hydrogen atom or a substituent, R⁹⁵ represents a hydrogen atom or a substituent, each of B⁹¹ to B⁹⁴ independently represents a nitrogen atom or C—R⁹⁶, R⁹⁶ represents a hydrogen atom or a substituent, each R⁹⁶ may be the same as or different from every other R⁹⁶, each of L⁹² and L⁹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁹¹ represents an atomic group for forming a bidentate ligand together with L⁹² and L⁹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁹¹ and S⁹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁹¹ or S⁹² may be the same as or different from every other S⁹¹ or S⁹².) [12]

The organic electroluminescence device according to [7],

wherein the metal complex represented by formula (2) is represented by the following formula (12).

(In formula (12), M¹²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹²³ to R¹²⁵ independently represents a hydrogen atom or a substituent, each of B¹²¹ to B¹²⁴ independently represents a nitrogen atom or C—R¹²⁶, R¹²⁶ represents a hydrogen atom or a substituent, each R¹²⁶ may be the same as or different from every other R¹²⁶, each of L¹²² and L¹²³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹²¹ represents an atomic group for forming a bidentate ligand together with L¹²² and L¹²³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹²¹ and S¹²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹²¹ or S¹²² may be the same as or different from every other S¹²¹ or S¹²².) [13]

The organic electroluminescence device according to [6],

wherein the metal complex represented by formula (1) is a metal complex represented by the following formula (13).

(In formula (13), each of A¹³¹ and A¹³² represents a nitrogen atom or a carbon atom, each of Y¹³¹ and Y¹³² represents a linking group or a single bond, each of L¹³¹ and L¹³² represents a partial structure having an atom bonded to Pt, each of Z¹³¹ and Z¹³² represents an aromatic nitrogen-containing heterocyclic ring, each of X¹³¹ and X¹³² represents an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom or a single bond, E¹³¹ represents a divalent linking group, each of S¹³¹ and S¹³² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹³¹ or S¹³² may be the same as or different from every other S¹³¹ or S¹³².) [14]

The organic electroluminescence device according to [13],

wherein the metal complex represented by formula (13) is represented by the following formula (14).

(In formula (14), wherein each of A¹⁴¹ to A¹⁴⁶ independently represents a nitrogen atom or a carbon atom, each of Z¹⁴¹ and Z¹⁴² independently represents an aromatic nitrogen-containing heterocyclic ring, each of Z¹⁴³ and Z¹⁴⁴ independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁴¹ represents a divalent linking group, each of S¹⁴¹ to S¹⁴⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁴¹, S¹⁴², S¹⁴³ or S¹⁴⁴ may be the same as or different from every other S¹⁴¹, S¹⁴², S¹⁴³ or S¹⁴⁴.) [15]

The organic electroluminescence device according to [14],

wherein the metal complex represented by formula (14) is represented by the following formula (15).

(In formula (15), each of A¹⁵¹ to A¹⁵⁴ independently represents a nitrogen atom or a carbon atom, each of R¹⁵³ to R¹⁵⁸ independently represents a hydrogen atom or a substituent, each of Z¹⁵¹ and Z¹⁵² independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁵¹ represents a divalent linking group, each of S¹⁵¹ to S¹⁵⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁵¹, S¹⁵², S¹⁵³ or S¹⁵⁴ may be the same as or different from every other S¹⁵¹, S¹⁵², S¹⁵³ or S¹⁵⁴.) [16]

The organic electroluminescence device according to [14],

wherein the metal complex represented by formula (14) is represented by the following formula (18).

(In formula (18), each of A¹⁸¹ to A¹⁸⁶ independently represents a nitrogen atom or a carbon atom, each of D¹⁸¹ to D¹⁸⁴ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D¹⁸¹, D¹⁸², A¹⁸¹, the nitrogen atom and the carbon atom or by D¹⁸³, D¹⁸⁴, A¹⁸⁴, the nitrogen atom and the carbon atom represents a single bond or a double bond, each of D¹⁸¹ to D¹⁸⁴ when these can be further substituted may have a substituent, each of Z¹⁸¹ and Z¹⁸² independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁸¹ represents a divalent linking group, each of S¹⁸¹ to S¹⁸⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁸¹, S¹⁸², S¹⁸³ or S¹⁸⁴ may be the same as or different from every other S¹⁸¹, S¹⁸², S¹⁸³ or S¹⁸⁴.) [17]

The organic electroluminescence device according to any one of [1] to [5],

wherein the metal complex having a group represented by formula (I) is a phosphorescent metal complex containing a monoanionic bidentate ligand represented by the following formulae (A1) to (A4) and a metal having an atomic weight of 40 or more.

(In formulae (A1) to (A4), each of E_(1a) to E_(1q) independently represents a carbon atom or a heteroatom, each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), and each of the structures represented by formulae (A1) to (A4) has a structure with 18 π-electrons in total.) [18]

The organic electroluminescence device according to [17],

wherein said phosphorescent metal complex contains a monoanionic bidentate ligand represented by the following formula (A1-3) or (A3-3) and a metal having an atomic weight of 40 or more.

(In formulae (A1-3) to (A3-3), each of E_(1f) to E_(1k) independently represents a carbon atom or a heteroatom, each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), and each of the structures represented by formulae (A1-3) and (A3-3) has a structure with 18 π-electrons in total.) [19]

The organic electroluminescence device according to [18],

wherein said phosphorescent metal complex is an iridium complex represented by the following formula (A9).

(In formula (9), each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to represents a group represented by formula (I), X-Y represents a monoanionic bidentate ligand, and n represents an integer of 1 to 3.) [20]

The organic electroluminescence device according to any one of [1] to [19],

wherein the metal complex having a group represented by formula (I) is contained in the light emitting layer.

[21]

The organic electroluminescence device according to any one of [1] to [20],

wherein a carbazole or indole structure-containing material is further contained in any one of the organic layer.

[22]

The organic electroluminescence device according to any one of [1] to [21],

wherein a carbazole or indole structure-containing material is further contained in the light emitting layer.

[23]

A composition containing a metal complex having a group represented by formula (I) in [1].

[24]

A light emitting layer containing a metal complex having a group represented by formula (I) in [1].

[25]

A light emission apparatus using the organic electroluminescence device according to any one of [1] to [22].

[26]

A display apparatus using the organic electroluminescence device according to any one of [1] to [22].

[27]

An illumination apparatus using the organic electroluminescence device according to any one of [1] to [22].

The organic electroluminescence device of the present invention contains a metal complex having a group represented by formula (I). By this configuration, an organic electroluminescence device (in the context of the present invention, this term is used with the same meaning as “the device of the present invention”) having high luminous efficiency (for example, external quantum efficiency) and high durability and causing little chromaticity shift after device deterioration can be provided. Also, a long life of the device can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing one example of the configuration of the organic electroluminescence device according to the present invention.

FIG. 2 is a schematic view showing one example of the light emission apparatus according to the present invention.

FIG. 3 is a schematic view showing one example of the illumination apparatus according to the present invention.

DESCRIPTION OF EMBODIMENTS

The organic electroluminescence device of the present invention is an organic electroluminescence device including a substrate having thereon a pair of electrodes and at least one organic layer between said electrodes, the organic layer containing a light emitting layer, wherein any one layer of the organic layer contains a metal complex having a group represented by the following formula (I):

(wherein R₁ represents an alkyl group, each of R₂ and R₃ independently represents a hydrogen atom or an alkyl group, n represents an integer of 0 to 6, and Z represents a saturated 5- to 8-membered ring).

The metal complex having a group represented by formula (I) includes its tautomers and is a metal complex having a group containing a specific saturated ring group. It has been considered that usually, when a secondary or tertiary carbon is substituted on an aromatic heterocyclic ring or an aromatic hydrocarbon ring, a hydrogen elimination reaction or a dimerization reaction from the excited state occurs, giving rise to decrease in the device life. However, introduction of a sterically bulky group is expected to bring about spatial separation of reactive sites of the light emitting material, whereby a hydrogen elimination reaction or dimerization reaction of the metal complex is suppressed and the device life is prolonged.

Particularly, in an organic electroluminescence device using, as the light emitting material, a metal complex of the present invention where a group containing a saturated ring group having quaternary carbon in a saturated 5- to 8-membered ring group is substituted on a ligand, that is, an aromatic heterocyclic ring or an aromatic hydrocarbon ring, the saturated ring group is sterically bulky but is more compactly and rigidly organized as compared with a chain group having the same number of atoms as the structure. Accordingly, the film state is considered to change by any form while keeping an appropriate intermolecular distance, whereby the degree of order in the molecular arrangement is increased, as a result, a charge career mobility in the device using the metal complex is increased, and an effect such as enhancement of the device efficiency and reduction of the drive voltage is obtained.

Also, by the stable film structure at driving, it is presumed that the metal complex can contribute also to the enhancement of durability.

Furthermore, in the embodiment where a saturated ring group as the group represented by formula (I) is combined to the ligand through a substituted or unsubstituted methylene group, the flexibility of the group represented by formula (I) is increased and the dispersibility of the light emitting material to the organic layer is enhanced as compared with the conventional alkyl group-substituted phosphorescent material, as a result, interaction of light emitting material molecules with each other is suppressed. These improved dispersibility and reduced interaction are presumed to enable more enhancing the device efficiency and easily obtaining an effect of reducing the chromaticity shift at the device deterioration.

According to the embodiment where a group represented by formula (I) having high flexibility is introduced, the solubility of the phosphorescent material in an organic solvent can be increased, and a high-concentration solution can be prepared. The coating step using a high-concentration solution is advantageous for improvement of the film homogeneity and reduction in impurities (dissolved oxygen, water), and an enhanced efficiency and a long life of a device fabricated by a wet process can be realized.

R₁ represents an alkyl group. Here, R₁ represents an alkyl group which may be substituted or may be linear or branched, and preferably represents an alkyl group having a carbon number of 1 to 12, more preferably from 1 to 6. R₁ is preferably an unsubstituted alkyl group, more preferably an unsubstituted linear alkyl group, still more preferably a methyl group or an ethyl group, and most preferably a methyl group.

Each of R₂ and R₃ independently represents a hydrogen atom or an alkyl group. Here, each of R₂ and R₃ independently represents a hydrogen atom or an alkyl group which may be substituted or may be linear or branched, and preferably represents an alkyl group having a carbon number of 1 to 12, more preferably from 1 to 6. Each of R₂ and R₃ is preferably a hydrogen atom or an unsubstituted alkyl group, more preferably a hydrogen atom or an unsubstituted linear alkyl group, still more preferably a hydrogen atom or a methyl group, yet still more preferably a hydrogen atom.

n represents an integer of 0 to 6, and n is preferably an integer of 1 to 6, more preferably an integer of 1 to 3, yet still more preferably 1.

When n is 1 or more, the flexibility of the group represented by formula (I) is increased and the dispersibility of the light emitting material to the organic layer is enhanced, as a result, interaction of light emitting material molecules with each other is suppressed. These improved dispersibility and reduced interaction are considered to enable enhancing the device efficiency and easily obtaining an effect of reducing the chromaticity shift at the device deterioration.

Z represents a saturated 5- to 8-membered ring, more preferably a 5- or 6-membered ring, together with C. The saturated 5- to 8-membered ring represented by Z is preferably formed of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom, more preferably formed of a carbon atom, a hydrogen atom and an oxygen atom, still more preferably formed of a carbon atom and a hydrogen atom.

Preferred examples of the saturated 5- to 8-membered ring represented by Z include a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a tetrahydrofuran ring, a tetrahydropyran ring, a tetrahydrothiophene ring, a dioxane ring, a pyrrolidine ring, a piperidine ring, a piperazine ring and a morpholine ring. Among these, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring and a cyclooctane ring are more preferred, and a cyclopentane ring and a cyclohexane ring are still more preferred.

The saturated 5- to 8-membered ring is generally excellent in the chemical stability as compared with a saturated 3- or 4-membered ring and therefore, the device of the present invention using a light emitting material having a group represented by formula (I) is considered to be excellent in the drive durability as compared with a device using a light emitting layer having a substituent containing a saturated 3- or 4-membered ring. Also, thanks to the bulky and rigid structure, the effect by the enhanced degree of order in the arrangement is considered to be great.

Furthermore, the group represented by formula (I) has a quaternary carbon atom in the saturated ring group and therefore, is bulky as well as rigid, and this is presumed to make larger the effect by the enhanced degree of order and enable obtaining an effect in terms of enhancement of the device efficiency, reduction of the drive voltage and improvement of the durability.

The saturated 5- to 8-membered ring represented by Z may further have a substituent thereon. Preferred examples of this substituent include an alkyl group, a cycloalkyl group and an aryl group.

Substituents a1 to a31 are illustrated below as preferred examples of the group represented by formula (1), but the present invention is not limited thereto.

Among these, a1, a2, a3, a5, a8, a9, a10, a12, a14, a15, a18, a19, a28, a29, a30 and a31 are preferred, a2, a5, a9, a12, a18, a19, a28 and a29 are more preferred, and a2, a5, a9 and a12 are still more preferred.

[Compound Represented by Formula (1)]

The compound represented by formula (1) is described in detail.

(In formula (1), M¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, A¹¹ represents a nitrogen atom or a carbon atom, X¹¹ represents an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom or a single bond, Y¹¹ represents a linking group or a single bond, L¹¹ represents a partial structure having an atom bonded to X¹¹, Z¹¹ represents an aromatic nitrogen-containing heterocyclic ring, each of L¹² and L¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹¹ represents an atomic group for forming a bidentate ligand together with L¹² and L¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each S¹¹ independently represents a group represented by formula (I), n represents an integer of 1 to 4, and each S¹¹ may be the same as or different from every other S¹¹).

M¹¹ represents a metal (may be a metal atom or ion) belonging to Groups 8 to 11 in the periodic table of elements and is preferably gold, copper, platinum, palladium, nickel, iridium rhodium, osmium or ruthenium, more preferably gold, platinum, palladium iridium or ruthenium, still more preferably gold, platinum, palladium or iridium, and most preferably platinum or iridium.

A¹¹ represents a nitrogen atom or a carbon atom and forms an aromatic nitrogen-containing heterocyclic ring together with the N atom and Z¹¹.

Examples of the aromatic nitrogen-containing heterocyclic ring represented by Z¹¹ in formula (1) include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a phthalazine ring, a carboline ring, and a ring where a carbon atom of a hydrocarbon ring constituting a carboline ring is further substituted with a nitrogen atom.

Z¹¹ is preferably a pyridine ring, a pyrimidine ring, a pyrazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, an isoquinoline ring or a quinoxaline ring, more preferably a pyridine ring, a pyrimidine ring, a pyrazine ring, an imidazole ring, a pyrazole ring, an isoquinoline ring or a quinoxaline ring, still more preferably an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring or a pyrazole ring.

The aromatic nitrogen-containing heterocyclic ring may have a substituent, and those described below as Substituent Group A can be applied to the substituent.

(Substituent Group A)

An alkyl group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 10, e.g., methyl, ethyl, isopropyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, trifluoromethyl, pentafluoroethyl), a cycloalkyl group (preferably having a carbon number of 3 to 30, more preferably from 3 to 20, still more preferably from 3 to 10, e.g., cyclopropyl, cyclopentyl, cyclohexyl), an alkenyl group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), an alkynyl group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, e.g., propargyl, 3-pentynyl),

an aryl group (preferably having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, e.g., phenyl, p-methylphenyl, naphthyl, anthranyl), an amino group (preferably having a carbon number of 0 to 30, more preferably from 0 to 20, still more preferably from 0 to 10, e.g., amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino), an alkoxy group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 10, e.g., methoxy, ethoxy, butoxy, 2-ethylhexyloxy), an aryloxy group (preferably having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, e.g., phenyloxy, 1-naphthyloxy, 2-naphthyloxy), a heterocyclic oxy group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy),

an acyl group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., acetyl, benzoyl, formyl, pivaloyl), an alkoxycarbonyl group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 12, e.g., methoxycarbonyl, ethoxycarbonyl), an aryloxycarbonyl group (preferably having a carbon number of 7 to 30, more preferably from 7 to 20, still more preferably from 7 to 12, e.g., phenyloxycarbonyl), an acyloxy group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, e.g., acetoxy, benzoyloxy), an acylamino group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, e.g., acetylamino, benzoylamino),

an alkoxycarbonylamino group (preferably having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 12, e.g., methoxycarbonylamino), an aryloxycarbonylamino group (preferably having a carbon number of 7 to 30, more preferably from 7 to 20, still more preferably from 7 to 12, e.g., phenyloxycarbonylamino), a sulfonylamino group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., methanesulfonylamino, benzenesulfonylamino), a sulfamoyl group (preferably having a carbon number of 0 to 30, more preferably from 0 to 20, still more preferably from 0 to 12, e.g., sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl),

a carbamoyl group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), an alkylthio group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., methylthio, ethylthio), an arylthio group (preferably having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, e.g., phenylthio), a heterocyclic thio group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., pyridylthio, 2-benzimizolylthio, 2-benzoxazolylthio, 2-benzothiazolylthio),

a sulfonyl group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., mesyl, tosyl), a sulfonyl group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., methanesulfinyl, benzenesulfinyl), a ureido group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., ureido, methylureido, phenylureido), a phosphoric acid amido group (preferably having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, e.g., diethylphosphoric acid amido, phenylphosphoric acid amido), a hydroxy group, a mercapto group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a fluorine atom),

a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (preferably having a carbon number of 1 to 30, more preferably from 1 to 12; examples of the heteroatom include a nitrogen atom, an oxygen atom and a sulfur atom; specifically an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a thienyl group, a piperidyl group, a morpholino group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a carbazolyl group, an azepinyl group and the like), a silyl group (preferably having a carbon number of 3 to 40, more preferably from 3 to 30, still more preferably from 3 to 24, e.g., trimethylsilyl, triphenylsilyl), and a silyloxy group (preferably having a carbon number of 3 to 40, more preferably from 3 to 30, still more preferably from 3 to 24, e.g., trimethylsilyloxy, triphenylsilyloxy). These substituents may be further substituted.

Also, a plurality of these substituents may combine with each other to form a ring.

The substituent of the aromatic nitrogen-containing heterocyclic ring is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

X¹¹ represents an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom or a single bond and is preferably an oxygen atom, a sulfur atom or a single bond, more preferably an oxygen atom or a single bond, still more preferably a single bond. In the case where X¹¹ represents a substituted nitrogen atom, the substituent is, for example, preferably a substituent selected from Substituent Group A, more preferably an alkyl group, a cycloalkyl group or an aryl group, still more preferably an alkyl group having a carbon number of 1 to 7 or an aryl group having a carbon number of 6 to 12 (number of ring members: from 1 to 2).

Y¹¹ represents a linking group or a single bond. The linking group is not particularly limited but is preferably a single bond or a divalent linking group containing a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, a germanium atom or a phosphorus atom, more preferably a single bond or a group selected from Linking Group A shown below.

Linking Group A:

In Linking Group A, each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² (R¹ to R¹²) independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. In the case where each of R¹ to R¹² represents a substituent, the substituent is preferably a substituent selected from Substituent Group A. Each of R¹ to R¹² when these can be substituted may further have a substituent, and R¹ and R², R³ and R⁴, R⁵ and R⁶, R³ and R⁵, R³ and R⁶, R⁴ and R⁶, or R¹⁰ and R¹¹ may combine with each other to form a ring.

Y¹¹ is more preferably a single bond or a substituent selected from Linking Group A. Among these, a single bond, —C(R¹)(R²)—, —C(R³)(R⁴)C(R⁵)(R⁶)—, —Si(R⁷)(R⁸)—, —N(R⁹)—, —O—, —S—, —SO—, —SO₂— and —CO— are preferred, a single bond, —C(R¹)(R²)—, —C(R³)(R⁴)C(R⁵)(R⁶)—, —Si(R⁷)(R⁸)—, —O— and —S— are more preferred, a single bond —C(R¹)(R²)— and —C(R³)(R⁴)C(R⁵)(R⁶)— are still more preferred, and a single bond is yet still more preferred.

In —C(R¹)(R²)—, each of R¹ and R² is preferably a hydrogen atom or a substituent selected from Substituent Group B below.

(Substituent Group B)

The substituent includes an alkyl group, a cycloalkyl group, an aryl group, a halogen atom, an amino group, an alkylthio group, an arylthio group, an alkyloxy group, an aryloxy group, a hydroxy group, a mercapto group and a halogen atom. Among these, an alkyl group, a cycloalkyl group, an aryl group, a halogen atom, an alkylthio group, an arylthio group, an alkyloxy group, an aryloxy group and a halogen atom are preferred, and an alkyl group and an aryl group are more preferred.

In —C(R³)(R⁴)C(R⁵)(R⁶)—, each of R³, R⁴, R⁵ and R⁶ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —Si(R⁷)(R⁸)—, each of R⁷ and R⁸ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —Ge(R¹⁰)(R¹¹)—, each of R¹⁰ and R¹¹ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —N(R⁹)—, R⁹ is preferably a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, more preferably an alkyl group or an aryl group, still more preferably an aryl group.

In —P(R¹²)—, R¹² has the same meaning as the preferred range of R⁹.

In formula (1), L¹¹ represents a partial structure having an atom bonded to X¹¹. The partial structure of L¹¹ is preferably a group bonded through a carbon atom, a group bonded through a nitrogen atom, a group bonded through a silicon atom, a group bonded through a phosphorus atom, a group bonded through an oxygen atom, or a group bonded through a sulfur atom, more preferably a group bonded through a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, still more preferably a group bonded through a carbon atom or an oxygen atom.

The group bonded through a carbon atom is preferably a substituted or unsubstituted aryl group bonded through a carbon atom, a substituted or unsubstituted 5-membered heteroaryl group bonded through a carbon atom, or a substituted or unsubstituted 6-membered heteroaryl group bonded through a carbon atom, more preferably a substituted or unsubstituted aryl group bonded through a carbon atom, a substituted or unsubstituted nitrogen-containing 5-membered heteroaryl group bonded through a carbon atom, or a nitrogen-containing 6-membered heteroaryl group bonded through a carbon atom, still more preferably a substituted aryl group bonded through a carbon atom.

The group bonded through an oxygen atom is preferably a substituted or unsubstituted hydroxyl group or a substituted or unsubstituted carboxyl group, more preferably a substituted or unsubstituted carboxyl group.

The group bonded through a nitrogen atom is preferably a substituted amino group or a nitrogen-containing 5-membered heteroaryl group bonded through a nitrogen atom, more preferably a nitrogen-containing 5-membered heteroaryl group bonded through a nitrogen atom, still more preferably a substituted carbazole group, a substituted pyrrole group or a substituted indole group.

The group bonded through a phosphorus atom is preferably a substituted phosphino group. The group bonded through a silicon atom is preferably a substituted silyl group. The group bonded through a sulfur atom is preferably a thiol group or a substituted thiol group.

Each of L¹² and L¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, and E¹¹ represents an atomic group for forming a bidentate ligand together with L¹² and L¹³. The combination of L¹² and L¹³ is not particularly limited but is preferably nitrogen atom-carbon atom, nitrogen atom-oxygen atom, or oxygen atom-oxygen atom. The bidentate ligand represented by L¹²-E¹¹-L¹³ is not particularly limited, but specific examples thereof include substituted or unsubstituted phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyridylpyridine, imidazolylpyridine, pyrazolylpyridine, triazolylpyridine, pyrazabole, diphenylphosphinoethylene, picolinic acid and acetylacetone. Among these, phenylpyridine, phenylpyrazole, phenylimidazole, pyridylpyridine, pyrazabole, picolinic acid and acetylacetone are preferred, and phenylpyridine, pyridylpyridine, picolinic acid and acetylacetone are more preferred. These groups may be further substituted with the above-described substituent.

k represents an integer of 1 to 3, l represents an integer of 0 to 2, and k+l is 2 or 3. l is preferably 1 or 0, more preferably 0.

S¹¹ represents a group represented by formula (I).

As the group represented by formula (I), substituents a1 to a31 are preferred, a1, a2, a3, a5, a8, a9, a10, a12, a14, a15, a18, a19, a28, a29, a30 and a31 are more preferred, a2, a5, a9, a12, a18, a19, a28 and a29 are still more preferred, and a2, a5, a9 and a12 are most preferred. This is presumed because all of bulkiness, rigidity and compactness are satisfied.

The group represented by formula (I) contains a quaternary carbon-containing saturated ring group in a saturated 5- to 8-membered ring and therefore, is sterically bulky but is more compactly and rigidly organized as compared with a chain group having the same number of atoms as the framework. Accordingly, the film state is considered to change by any form while keeping an appropriate intermolecular distance, whereby the degree of order in the molecular arrangement is increased, as a result, the device using, as the light emitting material, the metal complex having a group represented by formula (I) allows easy flow of a current, and an effect such as enhancement of the device efficiency and reduction of the drive voltage is obtained. Furthermore, thanks to the stable film structure at driving, it is presumed that the metal complex can contribute also to the enhancement of durability.

In addition, the saturated 5- to 8-membered ring is generally excellent in the chemical stability as compared with a saturated 3- or 4-membered ring and therefore, the device of the present invention using a light emitting material having a group represented by formula (I) is considered to be excellent in the drive durability as compared with a device using a light emitting layer having a substituent containing a saturated 3- or 4-membered ring. Also, thanks to the bulky and rigid structure, the effect by the enhanced degree of order in the arrangement is considered to be great.

n represents an integer of 1 to 4. n is preferably 1 or 2.

The compound represented by formula (1) is preferably represented by the following formula (2):

(In formula (2), M²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of A²¹ to A²³ independently represents a nitrogen atom or a carbon atom, Z²¹ represents an aromatic nitrogen-containing heterocyclic ring, Z²² represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, each of L²² and L²³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E²¹ represents an atomic group for forming a bidentate ligand together with L²² and L²³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S²¹ and S²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S²¹ or S²² may be the same as or different from every other S²¹ or S²²).

In formula (2), M²¹, A²¹, Z²¹, L²², L²³, E²¹, S²¹, S²², k and l have the same meanings as M¹¹, A¹¹, Z¹¹, L¹², L¹³, E¹¹, S¹¹, k and l in formula (1), and the preferred ranges are also the same.

Each of A²² and A²³ represents a nitrogen atom or a carbon atom, and these form an aromatic heterocyclic ring or an aromatic hydrocarbon ring together with Z²².

Examples of the aromatic heterocyclic ring or aromatic hydrocarbon ring represented by Z²² include a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a phenanthrene ring, a perylene ring, a pyridine ring, a quinoline ring, an isoquinoline ring, a phenanthridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, a cinnoline ring, an acridine ring, a phthalazine ring, a quinazoline ring, a quinoxaline ring, a naphthyridine ring, a pteridine ring, a pyrrole ring, a pyrazole ring, a triazole ring, an indole ring, a carbazole ring, an indazole ring, a benzimidazole ring, an oxazole ring, a thiazole ring, an oxadiazole ring, a thiadiazole ring, a benzoxazole ring, a benzothiazole ring, an imidazopyridine ring, a thiophene ring, a benzothiophene ring, a furan ring, a benzofuran ring, a phosphole ring, a phosphinine ring and a silole ring.

Z²² is preferably a benzene ring, a naphthalene ring, a benzoxazole ring, a pyrazole ring, an imidazole ring, a triazole ring, a pyridine ring, an indole ring or a thiophene ring, more preferably a benzene ring, a pyrazole ring, a pyridine ring, a benzoxazole ring or a thiophene ring.

Z²² may have a substituent, and those described above as Substituent Group A can be applied to the substituent. Furthermore, Z²² may form a condensed ring with other rings.

This substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

The compound represented by formula (2) is preferably represented by the following formula (3):

(In formula (3), M³¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of A³¹ and A³² independently represents a nitrogen atom or a carbon atom, each of R³³ to R³⁶ independently represents a hydrogen atom or a substituent, Z³² represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, each of L³² and L³³ independently represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E³¹ represents an atomic group for forming a bidentate ligand together with L³² and L³³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S³¹ and S³² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S³¹ or S³² may be the same as or different from every other S³¹ or S³²).

In formula (3), M³¹, A³¹, A³², Z³², L³², L³³, E³¹, S³¹, S³², n, m, k and l have the same meanings as M²¹, A²², A²³, Z²², L²², L²³, E²¹, S²¹, S²², n, m, k and l in formula (2), and the preferred ranges are also the same.

Each of R³³ to R³⁶ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (3) is preferably represented by the following formula (4):

(In formula (4), M⁴¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁴³ to R⁴⁶ independently represents a hydrogen atom or a substituent, each of B⁴¹ to B⁴⁴ independently represents a nitrogen atom or C—R⁴⁷, R⁴⁷ represents a hydrogen atom or a substituent, each R⁴⁷ may be the same as or different from every other R⁴⁷, each of L⁴² and L⁴³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁴¹ represents an atomic group for forming a bidentate ligand together with L⁴² and L⁴³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁴¹ and S⁴² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁴¹ or S⁴² may be the same as or different from every other S⁴¹ or S⁴²).

In formula (4), M⁴¹, R⁴³ to R⁴⁶, L⁴², L⁴³, E⁴¹, S⁴¹, S⁴², n, m, k and l have the same meanings as M³¹, R³³ to R³⁶, L³², L³³, E³¹, S³¹, S³², n, m, k and l in formula (3), and the preferred ranges are also the same.

Each of B⁴¹ to B⁴⁴ independently represents a nitrogen atom or C—R⁴⁷, and R⁴⁷ represents a hydrogen atom or a substituent. The combination of B⁴¹ to B⁴⁴ is not particularly limited but out of B⁴¹ to B⁴⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

As for the substituent represented by R⁴⁷, those described above as Substituent Group A can be applied.

Each R⁴⁷ may be the same as or different from every other R⁴⁷. R⁴⁷ may further have a substituent, and those described above as Substituent Group A can be applied to the substituent. Also, R⁴⁷'s may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

R⁴⁷ is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (4) is preferably represented by the following formula (5):

(In formula (5), M⁵¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁵³ to R⁵⁹ and R⁵¹⁰ independently represents a hydrogen atom or a substituent, each of L⁵² and L⁵³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁵¹ represents an atomic group for forming a bidentate ligand together with L⁵² and L⁵³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁵¹ and S⁵² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁵¹ or S⁵² may be the same as or different from every other S⁵¹ or S⁵²).

In formula (5), M⁵¹, L⁵², L⁵³, E⁵¹, S⁵¹, S⁵², k and l have the same meanings as M⁴¹, L⁴², L⁴³, E⁴¹, S⁴¹, S⁴², k and l in formula (4), and the preferred ranges are also the same.

Each of R⁵³ to R⁵⁹ and R⁵¹⁰ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably an alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

One preferred embodiment of formula (5) is represented by formula (5-1):

(In formula (5-1), M⁵¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁵¹³ to R⁵¹¹⁴ independently represents a hydrogen atom or a substituent, each of S⁵¹¹ and S⁵¹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁵¹¹ or S⁵¹² may be the same as or different from every other S⁵¹¹ or S⁵¹²).

In formula (5-1), M⁵¹¹, R⁵¹³ to R⁵¹⁶, R⁵¹⁷ to R⁵¹¹⁰, S⁵¹¹, S⁵¹², n and m have the same meanings as M⁵¹, R⁵³ to R⁵⁶, R⁵⁷ to R⁵¹⁰, S⁵¹, S⁵², n and m in formula (5), and the preferred ranges are also the same.

Each of R⁵¹¹¹ to R⁵¹¹⁴ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably an alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of R⁵¹¹¹ to R⁵¹¹⁴ is preferably a hydrogen atom.

One preferred embodiment of formula (5) is represented by formula (5-2):

(In formula (5-2), M⁵²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁵²³ to R⁵²¹³ independently represents a hydrogen atom or a substituent, each of S⁵²¹ and S⁵²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁵²¹ or S⁵²² may be the same as or different from every other S⁵²¹ or S⁵²²).

In formula (5-2), M⁵²¹, R⁵²³ to R⁵²⁶, R⁵²⁷ to R⁵²¹⁰, S⁵²¹, S⁵²², n and m have the same meanings as M⁵¹, R⁵³ to R⁵⁶, R⁵⁷ to R⁵¹⁰, S⁵¹, S⁵², n and m in formula (5), and the preferred ranges are also the same.

Each of R⁵²¹¹ to R⁵²¹³ independently represents a hydrogen atom or may have a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of R⁵²¹¹ to R⁵²¹³ is preferably a hydrogen atom, a methyl group or a tert-butyl group.

One preferred embodiment of formula (5) is represented by formula (5-3):

(In formula (5-3), M⁵³¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁵³³ to R⁵³¹⁰ independently represents a hydrogen atom or a substituent, each of S⁵³¹ and S⁵³² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁵³¹ or S⁵³² may be the same as or different from every other S⁵³¹ or S⁵³²).

In formula (5-3), M⁵³¹, R⁵³³ to R⁵³¹⁰, S⁵³¹, S⁵³², n and m have the same meanings as M⁵¹, R⁵³ to R⁵¹⁰, S⁵¹, S⁵², n and m in formula (5), and the preferred ranges are also the same.

The compound represented by formula (4) is preferably represented by the following formula (6):

(In formula (6), M⁶¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁶³ to R⁶⁶ independently represents a hydrogen atom or a substituent, each of B⁶¹ to B⁶³ independently represents a nitrogen atom or C—R⁶⁷, R⁶⁷ represents a hydrogen atom or a substituent, each R⁶⁷ may be the same as or different from every other R⁶⁷, each of L⁶² and L⁶³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁶¹ represents an atomic group for forming a bidentate ligand together with L⁶² and L⁶³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁶¹ and S⁶² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁶¹ or S⁶² may be the same as or different from every other S⁶¹ or S⁶²).

In formula (6), M⁶¹, L⁶², L⁶³, E⁶¹, S⁶¹, S⁶², k and l have the same meanings as M⁴¹, L⁴², L⁴³, E⁴¹, S⁴¹, S⁴², k and l in formula (4), and the preferred ranges are also the same.

R⁶³ to R⁶⁶ and B⁶¹ to B⁶³ have the same meanings as R⁴³ to R⁴⁶ and B⁴¹ to B⁴⁴ in formula (4), and the preferred ranges are also the same.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

One preferred embodiment of formula (6) is represented by formula (6-1):

(In formula (6-1), M⁶¹¹ a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁶¹³ to R⁶¹⁹ independently represents a hydrogen atom or a substituent, each of L⁶¹² and L⁶¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁶¹¹ represents an atomic group for forming a bidentate ligand together with L⁶¹² and L⁶¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁶¹¹ and S⁶¹² independently represents a group represented by formula (I), and each S⁶¹¹ or S⁶¹² may be the same as or different from every other S⁶¹¹ or S⁶¹²).

In formula (6-1), M⁶¹¹, R⁶¹³ to R⁶¹⁹, L⁶¹², L⁶¹³, E⁶¹¹, S⁶¹¹, S⁶¹², n, m, k and l have the same meanings as M⁶¹, R⁶³ to R⁶⁶, L⁶², L⁶³, E⁶¹, S⁶¹, S⁶², n, m, k and l in formula (6), and the preferred ranges are also the same.

Each of R⁶¹⁷ to R⁶¹⁹ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

One preferred embodiment of formula (6-1) is represented by formula (6-2):

(In formula (6-2), M⁶²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁶²³ to R⁶²⁹ independently represents a hydrogen atom or a substituent, each of S⁶²¹ and S⁶²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁶²¹ or S⁶²² may be the same as or different from every other S⁶²¹ or S⁶²²).

In formula (6-2), M⁶²¹, R⁶²³ to R⁶²⁶, R⁶²⁷ to R⁶²⁹, S⁶²¹, S⁶²², n and m have the same meaning as M⁶¹¹, R⁶¹³ to R⁶¹⁶, R⁶¹⁷ to R⁶¹⁹, S⁶¹¹, S⁶¹², n and m in formula (6-1), and the preferred ranges are also the same.

Each of R⁶²³ to R⁶²⁶ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

One preferred embodiment of formula (6-1) is represented by formula (6-3):

(In formula (6-3), M⁶³¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁶³³ to R⁶³¹² independently represents a hydrogen atom or a substituent, each of S⁶³¹ and S⁶³² independently represents a group represented by formula (I), and each S⁶³¹ or S⁶³² may be the same as or different from every other S⁶³¹ or S⁶³²).

In formula (6-3), M⁶³¹, R⁶³³ to R⁶³⁶, R⁶³⁷ to R⁶³⁹, S⁶³¹, S⁶³², n and m have the same meanings as M⁶¹¹, R⁶¹³ to R⁶¹⁶, R⁶¹⁷ to R⁶¹⁹, S⁶¹¹, S⁶¹² n and m in formula (6-1), and the preferred ranges are also the same.

Each of R⁶³¹⁰ to R⁶³¹² independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of R⁶³¹⁰ to R⁶³¹² is preferably a hydrogen atom, a methyl group or a tert-butyl group.

One preferred embodiment of formula (6-1) is represented by formula (6-4):

(In formula (6-4), M⁶⁴¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁶⁴³ to R⁶⁴⁹ independently represents a hydrogen atom or a substituent, each of S⁶⁴¹ and S⁶⁴² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁶⁴¹ or S⁶⁴² may be the same as or different from every other S⁶⁴¹ or S⁶⁴²).

In formula (6-4), M⁶⁴¹, R⁶⁴³ to R⁶⁴⁶, R⁶⁴⁷ to R⁶⁴⁹, S⁶⁴¹, S⁶⁴², n and m have the same meanings as M⁶¹¹, R⁶¹³ to R⁶¹⁶, R⁶¹⁷ to R⁶¹⁹, S⁶¹¹, S⁶¹², n and m in formula (6-1), and the preferred ranges are also the same.

The compound represented by formula (3) is preferably represented by the following formula (7):

(In formula (7), M⁷¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁷³ to R⁷⁶ independently represents a hydrogen atom or a substituent, each of A⁷¹ and A⁷² independently represents a nitrogen atom or a carbon atom, each of D⁷¹ to D⁷³ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D⁷¹ to D⁷³, A⁷¹ and A⁷² represents a single bond or a double bond, each of D⁷¹ to D⁷³ may have a substituent when these can be further substituted, each of L⁷² and L⁷³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁷¹ represents an atomic group for forming a bidentate ligand together with L⁷² and L⁷³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁷¹ and S⁷² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁷¹ or S⁷² may be the same as or different from every other S⁷¹ or S⁷²).

In formula (7), M⁷¹, R⁷³ to R⁷⁶. L⁷², L⁷³, E⁷¹, S⁷¹, S⁷², n, m, k and l have the same meanings as M³¹, R³³ to R³⁶, L³², L³³, E³¹, S³¹, S³², n, m, k and l in formula (3), and the preferred ranges are also the same.

Each of A⁷¹ and A⁷² represents a nitrogen atom or a carbon atom, and these form an aromatic heterocyclic ring or aromatic hydrocarbon ring together with D⁷¹ to D⁷³.

Each of D⁷¹ to D⁷³ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, and the bond between atoms in the 5-membered ring formed by D⁷¹ to D⁷³, A⁷¹ and A⁷² is not particularly limited but may be any combination of a single bond and a double bond. Each of D⁷¹ to D⁷³ is preferably a carbon atom or a nitrogen atom.

In the 5-membered ring formed by D⁷¹ to D⁷³, A⁷¹ and A⁷², the number of nitrogen atoms is preferably from 1 to 3, more preferably from 1 to 2.

Each of D⁷¹ to D⁷³ may have a substituent selected from Substituent Group A when these can be further substituted. The substituents may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

One preferred embodiment of formula (7) is represented by formula (7-1):

(In formula (7-1), M⁷¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁷¹³ to R⁷¹⁸ independently represents a hydrogen atom or a substituent, each of L⁷¹² and L⁷¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁷¹¹ represents an atomic group for forming a bidentate ligand together with L⁷¹² and L⁷¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁷¹¹ and S⁷¹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁷¹¹ or S⁷¹² may be the same as or different from every other S⁷¹¹ or S⁷¹²).

In formula (7-1), M⁷¹¹, R⁷¹³ to R⁷¹⁸, L⁷¹², L⁷¹³, E⁷¹¹, S⁷¹¹, S⁷¹², n, m, k and l have the same meanings as M⁷¹, R⁷³ to R⁷⁶, L⁷², L⁷³, E⁷¹, S⁷¹, S⁷², n, m, k and l in formula (7), and the preferred ranges are also the same.

The compound represented by formula (2) is preferably represented by the following formula (8):

(In formula (8), M⁸¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of A⁸¹ to A⁸³ independently represents a nitrogen atom or a carbon atom, each of D⁸¹ to D⁸³ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D⁸¹ to D⁸³, A⁸¹ and the N atom represents a single bond or a double bond, each of D⁸¹ to D⁸³ when these can be further substituted may have a substituent, Z⁸² represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, each of L⁸² and L⁸³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁸¹ represents an atomic group for forming a bidentate ligand together with L⁸² and L⁸³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁸¹ and S⁸² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁸¹ or S⁸² may be the same as or different from every other S⁸¹ or S⁸²).

In formula (8), M⁸¹, A⁸², A⁸³, Z⁸², L⁸², L⁸³, E⁸¹, S⁸¹, S⁸², n, m, k and l have the same meanings as M²¹, A²¹, A²², Z²², L²², L²³, E²¹, S²¹, S²², n, m, k and l in formula (2), and the preferred ranges are also the same.

Each of D⁸¹ to D⁸³ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, and the bond between atoms in the 5-membered ring formed by D⁸¹ to D⁸³, A⁸¹ and the nitrogen atom is not particularly limited but may be any combination of a single bond and a double bond. Each of D⁸¹ to D⁸³ is preferably a carbon atom or a nitrogen atom.

In the 5-membered ring formed by D⁸¹ to D⁸³, A⁸¹ and the nitrogen atom, the number of nitrogen atoms is preferably from 1 to 3, more preferably from 1 to 2.

Each of D⁸¹ to D⁸³ may have a substituent selected from Substituent Group A when these can be further substituted. The substituents may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (8) is preferably represented by the following formula (9):

(In formula (9), M⁹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R⁹³ and R⁹⁴ independently represents a hydrogen atom or a substituent, R⁹⁵ represents a hydrogen atom or a substituent, each of B⁹¹ to B⁹⁴ independently represents a nitrogen atom or C—R⁹⁶, R⁹⁶ represents a hydrogen atom or a substituent, each R⁹⁶ may be the same as or different from every other R⁹⁶, each of L⁹² and L⁹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E⁹¹ represents an atomic group for forming a bidentate ligand together with L⁹² and L⁹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S⁹¹ and S⁹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S⁹¹ or S⁹² may be the same as or different from every other S⁹¹ or S⁹²).

In formula (9), M⁹¹, L⁹², L⁹³, E⁹¹, S⁹¹, S⁹², n, m, k and l have the same meanings as M⁸¹, L⁸², L⁸³, E⁸¹, S⁸¹, S⁸², n, m, k and l in formula (8), and the preferred ranges are also the same.

Each of B⁹¹ to B⁹⁴ independently represents a nitrogen atom or C—R⁹⁶, and R⁹⁶ represents a hydrogen atom or a substituent. The combination of B⁹¹ to B⁹⁴ is not particularly limited but out of B⁹¹ to B⁹⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

Each of R⁹³ and R⁹⁴ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

R⁹⁵ represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, a trifluoromethyl group or an aryl group.

As for the substituent represented by R⁹⁶, those described above as Substituent Group A can be applied.

Each R⁹⁶ may be the same as or different from every other R⁹⁶. R⁹⁶ may further have a substituent, and those described above as Substituent Group A can be applied to the substituent. Also, R⁹⁶'s may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

R⁹⁶ is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (9) is preferably represented by the following formula (10):

(In formula (10), M¹⁰¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹⁰³ to R¹⁰⁸ independently represents a hydrogen atom or a substituent, R¹⁰⁹ represents a hydrogen atom or a substituent, each of L¹⁰² and L¹⁰³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹⁰¹ represents an atomic group for forming a bidentate ligand together with L¹⁰² and L¹⁰³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹⁰¹ and S¹⁰² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹⁰¹ or S¹⁰² may be the same as or different from every other S¹⁰¹ or S¹⁰²).

In formula (10), M¹⁰¹, L¹⁰², L¹⁰³, E¹⁰¹, S¹⁰¹, S¹⁰², k and l have the same meanings as M⁹¹, L⁹², L⁹³, S⁹¹, S⁹², k and l in formula (9), and the preferred ranges are also the same.

R¹⁰³ to R¹⁰⁸ have the same meanings as R⁹³ and R⁹⁴, and the preferred ranges are also the same.

R¹⁰⁹ has the same meaning as R⁹⁵, and the preferred range is also the same.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

The compound represented by formula (9) is preferably represented by the following formula (11):

(In formula (11), M¹¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹¹³ and R¹¹⁴ independently represents a hydrogen atom or a substituent, R¹¹⁵ represents a hydrogen atom or a substituent, each of B¹¹¹ to B¹¹³ independently represents a nitrogen atom or C—R¹¹⁶, R¹¹⁶ represents a hydrogen atom or a substituent, each R¹¹⁶ may be the same as or different from every other R¹¹⁶, each of L¹¹² and L¹¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹¹¹ represents an atomic group for forming a bidentate ligand together with L¹¹² and L¹¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹¹¹ and S¹¹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹¹¹ or S¹¹² may be the same as or different from every other S¹¹¹ or S¹¹²).

In formula (11), M¹¹¹, S¹¹¹, S¹¹², k and l have the same meanings as M⁹¹, S⁹¹, S⁹², k and l in formula (9), and the preferred ranges are also the same.

R¹¹³ and R¹¹⁴ have the same meanings as R⁹³ and R⁹⁴, and the preferred ranges are also the same.

R¹¹⁶ has the same meaning as R⁹⁵, and the preferred range is also the same.

B¹¹¹ to B¹¹⁴ have the same meanings as B⁹¹ to B⁹⁴, and the preferred ranges are also the same.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

One preferred embodiment of formula (11) is represented by formula (11-1):

(In formula (11-1), M¹¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹¹¹³ and R¹¹¹⁴ independently represents a hydrogen atom or a substituent, R¹¹¹⁵ represents a hydrogen atom or a substituent, each of R¹¹¹⁶ to R¹¹¹⁸ independently represents a hydrogen atom or a substituent, each of L¹¹¹² and L¹¹¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹¹¹¹ represents an atomic group for forming a bidentate ligand together with L¹¹¹² and L¹¹¹³ k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹¹¹¹ and S¹¹¹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹¹¹¹ or S¹¹¹² may be the same as or different from every other S¹¹¹¹ or S¹¹¹²).

In formula (11-1), M¹¹¹¹, R¹¹¹³, R¹¹¹⁴, R¹¹¹⁵, L¹¹¹², L¹¹¹³, E¹¹¹¹, S¹¹¹¹, S¹¹¹², n, m, k and l have the same meanings as M⁹¹, R⁹³, R⁹⁴, R⁹⁵, L⁹², L⁹³, E⁹¹, S⁹¹, S⁹², n, m, k and l in formula (9), and the preferred ranges are also the same.

Each of R¹¹¹⁶ to R¹¹¹⁸ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

One preferred embodiment of formula (11-1) is represented by formula (11-2):

(In formula (11-2), M¹¹²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹¹²³ and R¹¹²⁴ independently represents a hydrogen atom or a substituent, R¹¹²⁵ represents a hydrogen atom or a substituent, each of R¹¹²⁶ to R¹¹²⁸ and R¹¹²⁹ to R¹¹²¹² independently represents a hydrogen atom or a substituent, each of S¹¹²¹ and S¹¹²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹¹²¹ or S¹¹²² may be the same as or different from every other S¹¹²¹ or S¹¹²²).

In formula (11-2), M¹¹²¹, R¹¹²³, R¹¹²⁴, R¹¹²⁵, R¹¹²⁶ to R¹¹²⁸, S¹¹²¹, S¹¹²², n and m have the same meanings as M¹¹¹¹, R¹¹¹³, R¹¹¹⁴, R¹¹¹⁵, R¹¹¹⁶ to R¹¹¹⁸, S¹¹¹¹, S¹¹¹², n and m in formula (11-1), and the preferred ranges are also the same.

Each of R¹¹²⁹ to R¹¹²¹² independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of R¹¹²⁹ to R¹¹²¹² is preferably a hydrogen atom.

One preferred embodiment of formula (11-1) is represented by formula (11-3):

(In formula (11-3), M¹¹³¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹¹³³ and R¹¹³⁴ independently represents a hydrogen atom or a substituent, R¹¹³⁵ represents a hydrogen atom or a substituent, each of R¹¹³⁶ to R¹¹³⁸ and R¹¹³⁹ to R¹¹³¹¹ independently represents a hydrogen atom or a substituent, each of S¹¹³¹ and S¹¹³² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4).

In formula (11-3), M¹¹³¹, R¹¹³³, R¹¹³⁴, R¹¹³⁵, R¹¹³⁶ to R¹¹³⁸, S¹¹³¹, S¹¹³², n and m have the same meanings as M¹¹¹¹, R¹¹¹³, R¹¹¹⁴, R¹¹¹⁵, R¹¹¹⁶ to R¹¹¹⁸, S¹¹¹¹, S¹¹¹², n and m in formula (11-1), and the preferred ranges are also the same.

Each of R¹¹³⁹ to R¹¹³¹¹ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of R¹¹³⁹ to R¹¹³¹¹ is preferably a hydrogen atom or a methyl group.

One preferred embodiment of formula (11-1) is represented by formula (11-4):

(In formula (11-4), M¹¹⁴¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹¹⁴³ and R¹¹⁴⁴ independently represents a hydrogen atom or a substituent, R¹¹⁴⁵ represents a hydrogen atom or a substituent, each of R¹¹⁴⁶ to R¹¹⁴⁸ independently represents a hydrogen atom or a substituent, each of S¹¹⁴¹ and S¹¹⁴² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹¹⁴¹ or S¹¹⁴² may be the same as or different from every other S¹¹⁴¹ or S¹¹⁴²).

In formula (11-4), M¹¹⁴¹, R¹¹⁴³, R¹¹⁴⁴, R¹¹⁴⁵, R¹¹⁴⁶ to R¹¹⁴⁸, S¹¹⁴¹, S¹¹⁴², n and m have the same meanings as M¹¹¹¹, R¹¹¹³, R¹¹¹⁴, R¹¹¹⁵, R¹¹¹⁶ to R¹¹¹⁸, S¹¹¹¹, S¹¹¹², n and m in formula (11-1), and the preferred ranges are also the same.

The compound represented by formula (8) is preferably represented by the following formula (12):

(In formula (12), M¹²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹²³ to R¹²⁵ independently represents a hydrogen atom or a substituent, each of B¹²¹ to B¹²⁴ independently represents a nitrogen atom or C—R¹²⁶, R¹²⁶ represents a hydrogen atom or a substituent, each R¹²⁶ may be the same as or different from every other R¹²⁶, each of L¹²² and L¹²³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹²¹ represents an atomic group for forming a bidentate ligand together with L¹²² and L¹²³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹²¹ and S¹²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹²¹ or S¹²² may be the same as or different from every other S¹²¹ or S¹²²).

In formula (12), M¹²¹, L¹²², L¹²³, E¹²¹, S¹²¹, S¹²², n, m, k and l have the same meanings as M⁸¹, L⁸², L⁸³, E⁸¹, S⁸¹, S⁸², n, m, k and l in formula (8), and the preferred ranges are also the same.

Each of R¹²³ to R¹²⁵ independently represents a hydrogen atom or a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of B¹²¹ to B¹²⁴ independently represents a nitrogen atom or C—R¹²⁶, and R¹²⁶ represents a hydrogen atom or a substituent. The combination of B¹²¹ to B¹²⁴ is not particularly limited but out of B¹²¹ to B¹²⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

As for the substituent represented by R¹²⁶, those described above as Substituent Group A can be applied.

Each R¹²⁶ may be the same as or different from every other R¹²⁶. R¹²⁶ may further have a substituent, and those described above as Substituent Group A can be applied to the substituent. Also, R¹²⁶'s may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

R¹²⁶ is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

One preferred embodiment of formula (12) is represented by formula (12-1):

(In formula (12-1), M¹²¹¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹²¹³ to R¹²¹⁵ independently represents a hydrogen atom or a substituent, each of B¹²¹¹ to B¹²¹³ independently represents a nitrogen atom or C—R¹²¹⁶, R¹²¹⁶ represents a hydrogen atom or a substituent, each R¹²¹⁶ may be the same as or different from every other R¹²¹⁶, each of L¹²¹² and L¹²¹³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹²¹¹ represents an atomic group for forming a bidentate ligand together with L¹²¹² and L¹²¹³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹²¹¹ and S¹²¹² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹²¹¹ or S¹²¹² may be the same as or different from every other S¹²¹¹ or S¹²¹²).

In formula (12-1), M¹²¹¹, R¹²¹³ to R¹²¹⁵, B¹²¹¹ to B¹²¹³, L¹²¹², L¹²¹³, E¹²¹¹, S¹²¹¹, S¹²¹², n, m, k and l have the same meanings as M¹²¹, R¹²³ to R¹²⁵, B¹²¹ to B¹²⁴, L¹²², L¹²³, E¹²¹, S¹²¹, S¹²², n, m, k and l in formula (12), and the preferred ranges are also the same.

Formula (12) is preferably represented by formula (12-2).

(In formula (12-2), M¹²²¹ represents a metal belong to Groups 8 to 11 in the periodic table of elements, each of R¹²²³ to R¹²²⁹ independently represents a hydrogen atom or a substituent, each of L¹²²² and L¹²²³ represents a carbon atom, a nitrogen atom, an oxygen atom or a phosphorus atom, E¹²²¹ represents an atomic group for forming a bidentate ligand together with L¹²²² and L¹²²³, k represents an integer of 1 to 3, l represents an integer of 0 to 2, k+l is 2 or 3, each of S¹²²¹ and S¹²²² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹²²¹ or S¹²²² may be the same as or different from every other S¹²²¹ or S¹²²²).

In formula (12-2), M¹²²¹, R¹²²³ to R¹²²⁵, L¹²²², L¹²²³, E¹²²¹, S¹²²¹, S¹²²², n, m, k and l have the same meanings as M¹²¹, R¹²³ to R¹²⁵, L¹²², L¹²³, E¹²¹, S¹²¹, S¹²², n, m, k and l in formula (12), and the preferred ranges are also the same.

Each of R¹²²⁶ to R¹²²⁹ independently represents a hydrogen atom or may have a substituent selected from substituents including Substituent Group A, and the preferred ranges are the same as that of R¹²⁶ in formula (12).

The compound represented by formula (1) is preferably represented by the following formula (13):

(In formula (13), each of A¹³¹ and A¹³² represents a nitrogen atom or a carbon atom, each of Y¹³¹ and Y¹³² represents a linking group or a single bond, each of L¹³¹ and L¹³² represents a partial structure having an atom bonded to Pt, each of Z¹³¹ and Z¹³² represents an aromatic nitrogen-containing heterocyclic ring, each of X¹³¹ and X¹³² represents an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom or a single bond, E¹³¹ represents a divalent linking group, each of S¹³¹ and S¹³² independently represents a group represented by formula (I), each of n and m represents an integer of 0 to 4, n+m is an integer of 1 to 4, and each S¹³¹ or S¹³² may be the same as or different from every other S¹³¹ or S¹³²).

In formula (13), A¹³¹ to A¹³⁶, Z¹³¹ to Z¹³⁴, S¹³¹ to S¹³⁴, L¹³¹, L¹³², X¹³¹, X¹³², Y¹³¹, Y¹³², n, m, k and l have the same meanings as A¹¹ to A¹³, Z¹¹, Z¹², S¹¹, S¹², L¹¹, X¹¹, Y¹¹, n, m, k and l in formula (1), and the preferred ranges are also the same.

E¹³¹ represents a divalent linking group. The linking group is not particularly limited but is preferably a divalent linking group composed of a single bond, a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom or a germanium atom, more preferably a group selected from Linking Group A.

E¹³¹ is preferably a substituent selected from Linking Group A, and among these, —C(R¹)(R²)—, —C(R³)(R⁴)C(R⁵)(R⁶)—, —Si(R⁷)(R⁸)—, —N(R⁹)—, —O—, —S—, —SO—, —SO₂— and —CO— are preferred, —C(R¹)(R²)—, —C(R³)(R⁴)C(R⁵)(R⁶)—, —Si(R⁷)(R⁸)—, —O— and —S— are more preferred, —C(R¹)(R²)— and —C(R³)(R⁴)C(R⁵)(R⁶)— are still more preferred.

In —C(R¹)(R²)—, each of R¹ and R² is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —C(R³)(R⁴)C(R⁵)(R⁶)—, each of R³, R⁴, R⁵ and R⁶ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —Si(R⁷)(R⁸)—, each of R⁷ and R⁸ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —Ge(R¹⁰)(R¹¹)—, each of R¹⁰ and R¹¹ is preferably a hydrogen atom or a substituent selected from Substituent Group B.

In —N(R⁹)—, R⁹ is preferably a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, more preferably an alkyl group or an aryl group, still more preferably an aryl group.

In —P(R¹²)—, R¹² has the same meaning as the preferred range of R⁹.

In formula (13), examples of the aromatic nitrogen-containing heterocyclic ring represented by Z¹³¹ and Z¹³² include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a phthalazine ring, a carboline ring, and a ring where a carbon atom of a hydrocarbon ring constituting a carboline ring is further substituted with a nitrogen atom.

Each of Z¹³¹ and Z¹³² is preferably a pyridine ring, a pyrimidine ring, a pyrazine ring, a benzimidazole ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzothiazole ring, a benzoxazole ring, an isoquinoline ring or a quinoxaline ring, more preferably a pyridine ring, a pyrimidine ring, a pyrazine ring, an imidazole ring, a pyrazole ring, an isoquinoline ring or a quinoxaline ring, still more preferably an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring or a pyrazole ring.

The aromatic nitrogen-containing heterocyclic ring may have a substituent, and those described as Substituent Group A can be applied to the substituent.

The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, stil, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (13) is preferably represented by the following formula (14):

(In formula (14), each of A¹⁴¹ to A¹⁴⁶ independently represents a nitrogen atom or a carbon atom, each of Z¹⁴¹ and Z¹⁴² independently represents an aromatic nitrogen-containing heterocyclic ring, each of Z¹⁴³ and Z¹⁴⁴ independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁴¹ represents a divalent linking group, each of S¹⁴¹ to S¹⁴⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁴¹, S¹⁴², S¹⁴³ or S¹⁴⁴ may be the same as or different from every other S¹⁴¹, S¹⁴², S¹⁴³ or S¹⁴⁴).

In formula (14), A¹⁴¹ to A¹⁴⁶, Z¹⁴¹ to Z¹⁴⁴, S¹⁴¹ to S¹⁴⁴, E¹⁴¹, n, m, k and l have the same meanings as A¹³¹ to A¹³³, Z¹³¹, Z¹³², S¹³¹, S¹³², E¹³¹, m, k and l in formula (13), and the preferred ranges are also the same.

Each of n and m represents an integer of 0 to 4, and n+m is an integer of 1 to 4. n+m is preferably 1 or 2.

The compound represented by formula (14) is preferably represented by the following formula (15):

(In formula (15), each of A¹⁵¹ to A¹⁵⁴ independently represents a nitrogen atom or a carbon atom, each of R¹⁵³ to R¹⁵⁸ independently represents a hydrogen atom or a substituent, each of Z¹⁵¹ and Z¹⁵² independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁵¹ represents a divalent linking group, each of S¹⁵¹ to S¹⁵⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁵¹, S¹⁵², S¹⁵³ or S¹⁵⁴ may be the same as or different from every other S¹⁵¹, S¹⁵², S¹⁵³ or S¹⁵⁴).

In formula (15), A¹⁵¹, A¹⁵², A¹⁵³, A¹⁵⁴, Z¹⁵¹, Z¹⁵², E¹⁵¹, S¹⁵¹ to S¹⁵⁴, n, m, k and l have the same meanings as A¹⁴², A¹⁴³, A¹⁴⁵, A¹⁴⁶, Z¹⁴³, Z¹⁴⁴, E¹⁴¹, S¹⁴¹ to S¹⁴⁴, n, m, k and l in formula (14), and the preferred ranges are also the same.

Each of R¹⁵³ to R¹⁵⁸ independently represents a hydrogen atom or may have a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (15) is preferably represented by the following formula (16):

(In formula (16), each of R¹⁶³ to R¹⁶⁸ independently represents a hydrogen atom or a substituent, each of B¹⁶¹ to B¹⁶⁸ independently represents a nitrogen atom or C—R¹⁶⁹, R¹⁶⁹ represents a hydrogen atom or a substituent, each R¹⁶⁹ may be the same as or different from every other R¹⁶⁹, E¹⁶¹, represents a divalent linking group, each of S¹⁶¹ to S¹⁶⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁶¹, S¹⁶², S¹⁶³ or S¹⁶⁴ may be the same as or different from every other S¹⁶¹, S¹⁶², S¹⁶³ or S¹⁶⁴).

In formula (16), R¹⁶³ to R¹⁶⁸, E¹⁶¹, S¹⁶¹ to S¹⁶⁴, n, m, k and l have the same meanings as R¹⁵³ to R¹⁵⁸, E¹⁵¹, S¹⁵¹ to S¹⁵⁴, n, m, k and l in formula (15), and the preferred ranges are also the same.

Each of B¹⁶¹ to B¹⁶⁸ independently represents a nitrogen atom or C—R¹⁶⁹, and R¹⁶⁹ represents a hydrogen atom or a substituent. The combination of B¹⁶¹ to B¹⁶⁴ is not particularly limited but out of B¹⁶¹ to B¹⁶⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1, and out of B¹⁶⁵ to B¹⁶⁸, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

As for the substituent represented by R¹⁶⁹, those described as Substituent Group A can be applied.

Each R¹⁶⁹ may be the same as or different from every other R¹⁶⁹. R¹⁶⁹ may further have a substituent, and those described above as Substituent Group A can be applied to the substituent. Also, R¹⁶⁹'s may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

R¹⁶⁹ is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (15) is preferably represented by the following formula (17):

(In formula (17), each of R¹⁷³ to R¹⁷⁸ independently represents a hydrogen atom or a substituent, each of A¹⁷¹ to A¹⁷⁴ independently represents a nitrogen atom or a carbon atom, each of D¹⁷¹ to D¹⁷⁶ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D¹⁷¹ to D¹⁷³, A¹⁷¹ and A¹⁷² or by D¹⁷⁴ to D¹⁷⁶, A¹⁷³ and A¹⁷⁴ represents a single bond or a double bond, each of D¹⁷¹ to D¹⁷⁶ when these can be further substituted may have a substituent, E¹⁷¹ represents a divalent linking group, each of S¹⁷¹ to S¹⁷⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁷¹, S¹⁷², S¹⁷³ or S¹⁷⁴ may be the same as or different from every other S¹⁷¹, S¹⁷², S¹⁷³ or S¹⁷⁴).

In formula (17), R¹⁷³ to R¹⁷⁸, E¹⁷¹, S¹⁷¹ to S¹⁷⁴, n, m, k and l have the same meanings as R¹⁵³ to R¹⁵⁸, E¹⁵¹, S¹⁵¹ to S¹⁵⁴, n, m, k and l in formula (15), and the preferred ranges are also the same.

Each of A¹⁷¹, A¹⁷², A¹⁷³ and A¹⁷⁴ independently represents a nitrogen atom or a carbon atom. A¹⁷¹ and A¹⁷² form an aromatic heterocyclic ring or an aromatic hydrocarbon ring together with D¹⁷¹ to D¹⁷³, and A¹⁷³ and A¹⁷⁴ form an aromatic heterocyclic ring or an aromatic hydrocarbon ring together with D¹⁷⁴ to D¹⁷⁶.

Each of D¹⁷¹ to D¹⁷³ and D¹⁷⁴ to D¹⁷⁶ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon. The bond between atoms in the 5-membered ring formed by A¹⁷¹, A¹⁷² and D¹⁷¹ to D¹⁷³ or by A¹⁷³, A¹⁷⁴ and D¹⁷⁴ to D¹⁷⁶ is not particularly limited but may be any combination of a single bond and a double bond. Each of D¹⁷¹ to D¹⁷³ and D¹⁷⁴ to D¹⁷⁶ is preferably a carbon atom or a nitrogen atom.

In the 5-membered ring formed by A¹⁷¹, A¹⁷² and D¹⁷¹ to D¹⁷³ or by A¹⁷³, A¹⁷⁴ and D¹⁷⁴ to D¹⁷⁶, the number of nitrogen atoms is preferably from 1 to 3, more preferably from 1 to 2.

Each of D¹⁷¹ to D¹⁷³ and D¹⁷⁴ to D¹⁷⁶ when these can be further substituted may have a substituent selected from Substituent Group A. The substituents may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

The substituent thereof is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (14) is preferably represented by the following formula (18):

(In formula (18), each of A¹⁸¹ to A¹⁸⁶ independently represents a nitrogen atom or a carbon atom, each of D¹⁸¹ to D¹⁸⁴ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D¹⁸¹, D¹⁸², A¹⁸¹, the nitrogen atom and the carbon atom or by D¹⁸³, D¹⁸⁴, A¹⁸⁴, the nitrogen atom and the carbon atom represents a single bond or a double bond, each of D¹⁸¹ to D¹⁸⁴ when these can be further substituted may have a substituent, each of Z¹⁸¹ and Z¹⁸² independently represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, E¹⁸¹ represents a divalent linking group, each of S¹⁸¹ to S¹⁸⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁸¹, S¹⁸², S¹⁸³ or S¹⁸⁴ may be the same as or different from every other S¹⁸¹, S¹⁸², S¹⁸³ or S¹⁸⁴).

In formula (18), A¹⁸², A¹⁸³, A¹⁸⁵, A¹⁸⁶, Z¹⁸¹, Z¹⁸², E¹⁸¹, S¹⁸¹ to S¹⁸⁴, n, m, k and l have the same meanings as A¹⁴², A¹⁴³, A¹⁴⁵, A¹⁴⁶, Z¹⁴³, Z¹⁴⁴, E¹⁴¹, S¹⁴¹ to S¹⁴⁴, n, m, k and l in formula (14), and the preferred ranges are also the same.

Each of D¹⁸¹, D¹⁸², D¹⁸³ and D¹⁸⁴ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon. The bond between atoms in the 5-membered ring formed by D¹⁸¹, D¹⁸², A¹⁸¹, the nitrogen atom and the carbon atom or by D¹⁸³, D¹⁸⁴, A¹⁸⁴, the nitrogen atom and the carbon atom is not particularly limited but may be any combination of a single bond and a double bond. Each of D¹⁸¹, D¹⁸², D¹⁸³ and D¹⁸⁴ is preferably a carbon atom or a nitrogen atom.

In the 5-membered ring formed by D¹⁸¹, D¹⁸², A¹⁸¹, the nitrogen atom and the carbon atom or by D¹⁸³, D¹⁸⁴, A¹⁸⁴, the nitrogen atom and the carbon atom, the number of nitrogen atoms is preferably from 1 to 3, more preferably from 1 to 2.

Each of D¹⁸¹, D¹⁸², D¹⁸³ and D¹⁸⁴ when these can be further substituted may have a substituent selected from Substituent Group A. The substituents may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (18) is preferably represented by the following formula (19):

(In formula (19), each of A¹⁹¹ and A¹⁹² independently represents a nitrogen atom or a carbon atom, each of D¹⁹¹ to D¹⁹⁴ independently represents an atom selected from carbon, nitrogen, oxygen, sulfur and silicon, the bond between atoms in the 5-membered ring formed by D¹⁹¹, D¹⁹², A¹⁹¹, the nitrogen atom and the carbon atom or by D¹⁹³, D¹⁹⁴, A¹⁹⁴, the nitrogen atom and the carbon atom represents a single bond or a double bond, each of D¹⁹¹ to D¹⁹⁴ when these can be further substituted may have a substituent, each of B¹⁹¹ to B¹⁹⁸ independently represents a nitrogen atom or C—R¹⁹⁹, R¹⁹⁹ represents a hydrogen atom or a substituent, each R¹⁹⁹ may be the same as or different from every other R¹⁹⁹, E¹⁹¹ represents a divalent linking group, each of S¹⁹¹ to S¹⁹⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S¹⁹¹, S¹⁹², S¹⁹³ or S¹⁹⁴ may be the same as or different from every other S¹⁹¹, S¹⁹², S¹⁹³ or S¹⁹⁴).

In formula (19), E¹⁹¹, S¹⁹¹ to S¹⁹⁴, n, m, k and l have the same meanings as E¹⁸¹, S¹⁸¹ to S¹⁸⁴, n, m, k and l in formula (18), and the preferred ranges are also the same.

Each of B¹⁹¹ to B¹⁹⁸ independently represents a nitrogen atom or C—R¹⁹⁷, and R¹⁹⁷ represents a hydrogen atom or a substituent. The combination of B¹⁹¹ to B¹⁹⁸ is not particularly limited but out of B¹⁹¹ to B¹⁹⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1, and out of B¹⁹⁵ to B¹⁹⁸, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

As for the substituent represented by R¹⁹⁷, those described as Substituent Group A can be applied.

Each R¹⁹⁷ may be the same as or different from every other R¹⁹⁷. R¹⁹⁷ may further have a substituent, and those described above as Substituent Group A can be applied to the substituent. Also, R¹⁹⁷'s may combine with each other to form a condensed ring, and examples of the ring formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyridazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an oxadiazole ring, a thiazole ring, a thiadiazole ring, a furan ring, a thiophene ring, a selenophene ring, a silole ring, a germole ring and a phosphole ring.

R¹⁹⁷ is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

The compound represented by formula (19) is preferably represented by the following formula (20):

(In formula (20), each of R²⁰³ to R²⁰⁶ independently represents a hydrogen atom or a substituent, each of B²⁰¹ to B²⁰⁸ independently represents a nitrogen atom or C—R²⁰⁷, R²⁰⁷ represents a hydrogen atom or a substituent, each R²⁰⁷ may be the same as or different from every other R²⁶⁷, E²⁰¹ represents a divalent linking group, each of S²⁰¹ to S²⁰⁴ independently represents a group represented by formula (I), and each S²⁰¹, S²⁰², S²⁰³ or S²⁰⁴ may be the same as or different from every other S²⁰¹, S²⁰², S²⁰³ or S²⁰⁴).

In formula (20), E²⁰¹, S²⁰¹ to S²⁰⁴, B²⁰¹ to B²⁰⁸, R²⁰³ to R²⁰⁷, n, m, k and l have the same meanings as E¹⁹¹, S¹⁹¹ to S¹⁹⁴, B¹⁹¹ to B¹⁹⁸, R¹⁹¹ to R¹⁹⁷, n, m, k and l in formula (19), and the preferred ranges are also the same.

The compound represented by formula (19) is preferably represented by the following formula (21):

(In formula (21), each of R²¹³ and R²¹⁴ independently represents a hydrogen atom or a substituent, each of R²¹⁵ and R²¹⁶ independently represents a hydrogen atom or a substituent, each of B²¹¹ to B²¹⁸ independently represents a nitrogen atom or C—R²¹⁷, R²¹⁷ represents a hydrogen atom or a substituent, each R²¹⁷ may be the same as or different from every other R²¹⁷, E²¹¹ represents a divalent linking group, each of S²¹¹ to S²¹⁴ independently represents a group represented by formula (I), each of n, m, k and l represents an integer of 0 to 4, n+m+k+l is an integer of 1 to 4, and each S²¹¹, S²¹², S²¹³ or S²¹⁴ may be the same as or different from every other S²¹¹, S²¹², S²¹³ or S²¹⁴).

In formula (21), E²¹¹, S²¹¹ to S²¹⁴, n, m, k and l have the same meanings as E¹⁷¹, S¹⁷¹ to S¹⁷⁴, n, m, k and l in formula (17), and the preferred ranges are also the same.

Each of B²¹¹ to B²¹⁸ independently represents a nitrogen atom or C—R²¹⁷, and R²¹⁷ represents a hydrogen atom or a substituent. The combination of B²¹¹ to B²¹⁸ is not particularly limited but out of B²¹¹ to B²¹⁴, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1, and out of B²¹⁵ to B²¹⁸, the number of nitrogen atoms is preferably from 0 to 2, more preferably from 0 to 1.

Each of R²¹³ to R²¹⁶ independently represents a hydrogen atom or may have a substituent selected from substituents including Substituent Group A. The substituent is preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a sulfo group, a carboxyl group, a nitro group, a sulfino group, a heterocyclic group or a silyl group, more preferably a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a cyano group, a fluorine atom or a heterocyclic group, still more preferably a substituted or unsubstituted alkyl group, a fluorine atom, a methoxy group, an aryl group or a cyano group. In particular, the substituent is preferably a substituted or unsubstituted alkyl group, a fluorine atom or a cyano group, and most preferably a methyl group, a trifluoromethyl group, a fluorine atom or a cyano group.

Each of the compounds represented by formulae (1) to (21) may be a polymer compound having the compound in the main or side chain.

The polymer compound may be a homopolymer compound or a copolymer, and the copolymer may be any of a random copolymer, an alternating copolymer and a block copolymer. In the case of a copolymer, the other monomer is preferably a monomer having a charge transport function moiety. Examples of the monomer having a charge transport function include a material having in its partial structure a compound described later as the host material, the material contained in the hole transporting layer, or the material contained in the electron transporting material. A monomer having in its partial structure a compound described as the host material is preferred.

In the case of a polymer compound, the molecular weight is preferably from 2,000 to less than 1,000,000, more preferably from 10,000 to less than 500,000, still more preferably from 10,000 to less than 100,000.

Specific examples of the compound represented by formula (1) for use in the present invention are illustrated below, but the present invention is not limited thereto.

Other specific examples are illustrated below.

These compounds can be synthesized by various known synthesis methods described, for example, in Org. Lett., 3, 2579-2581 (2001), Inorg. Chem., 30, 1685-1687 (1991), J. Am. Chem. Soc., Vol. 123, 4304 (2001), Inorg. Chem., Vol. 40, 1704-1711 (2001), Inorg. Chem., 41, 3055-3066 (2002), and Eur. J. Org. Chem., 4, 695-709 (2004).

Furthermore, the above-described metal complex compounds can be synthesized by various techniques such as the method described in Journal of Organic Chemistry, 53, 786 (1988), G. R. Newkome et al., at page 789, from left column, line 53 to right column, line 7, the method described at page 790, left column, lines 18 to 38, the method described at page 790, right column, lines 19 to 30, a combination thereof, and the method described in Chemische Berichte, 113, 2749 (1980), H. Lexy et al., at page 2752, liens 26 to 35.

For example, a ligand or a dissociation product thereof and a metal compound are reacted with or without a solvent (for example, a halogen-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, a ketone-based solvent, a nitrile-based solvent, an amide-based solvent, a sulfone-based solvent, a sulfoxide-based solvent or water) in the presence or absence of a base (various inorganic or organic bases, for example, sodium methoxide, tert-butoxy potassium, triethylamine or potassium carbonate) at not higher than room temperature or under heating (in addition to normal heating, microwave heating is also effective), whereby the compound can be obtained.

In another embodiment of the present invention, the metal complex having a group represented by formula (I) is preferably a phosphorescent metal complex containing a monoanionic bidentate ligand represented by the following formulae (A1) to (A4) and a metal having an atomic weight of 40 or more.

Incidentally, in the formulae of ligands for use in the present invention, * is a coordination site to a metal, and each of the bond between E_(1a) and the metal and the bond between E_(1p) and the metal may be individually either a covalent bond or a coordinate bond.

The bidentate ligand represented by the following formulae (A1) to (A4) is described below.

[Bidentate Ligand Represented by Formulae (A1) to (A4)]

(In formulae (1) to (4), each of E_(1a) to E_(1q) independently represents a carbon atom or a heteroatom, each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), and each of the frameworks represented by formulae (A1) to (A4) has a structure with 18 π-electrons in total).

At least one of R_(1a) to R_(1i) represents a group represented by formula (I).

As the group represented by formula (I) in R_(1a) to R_(1i), substituents a1 to a31 are preferred, a1, a2, a3, a5, a8, a9, a10, a12, a14, a15, a18, a19, a28, a29, a30 and a31 are more preferred, a2, a5, a9, a12, a14, a19, a28 and a29 are still more preferred, and a2, a5, a9 and a12 are most preferred. This is presumed because all of bulkiness, rigidity and compactness are satisfied.

Preferably, at least one of R_(1a), R_(1b), R_(1d), R_(1e), R_(1g) and R_(1h) is a group represented by formula (I), and more preferably, at least one of R_(1a), R_(1b), R_(1d) and R_(1e) is a group represented by formula (I). In formulae A1 and A2, still more preferably, at least one of R_(1a), R_(1b) and R_(1d) is a group represented by formula (I), and yet still more preferably, at least one of R_(1a) and R_(1d) is a group represented by formula (I). In formulae A3 and A4, still more preferably, at least one of R_(1a), R_(1b) and R_(1d) is a group represented by formula (I), and yet still more preferably, at least one of R_(1a), R_(1c) and R_(1d) is a group represented by formula (I).

The bidentate ligand may combine with other ligands to form a tridentate, tetradentate, a pentadentate or hexadentate ligand.

Each of E_(1a) to E_(1q) is selected from a carbon atom and a hetero atom, preferably selected from a carbon atom and a nitrogen atom. E_(1a) and E_(1p) are preferably different atoms. The metal complex has a structure with 18 π-electrons.

The ring composed of E_(1a) to E_(1q) represents a 5-membered heterocycle, more specifically, oxazole, thiazole, isoxazole, isothiazole, pyrrole, imidazole, pyrazole, triazole, or tetrazole, preferably imidazole or pyrazole, more preferably imidazole. This 5-membered ring may form a condensed ring with other rings.

At least one of E_(1a) to E_(1e) preferably represents a nitrogen atom; more preferably, two or three of E_(1a) to E_(1e) represent a nitrogen atom; and still more preferably, two of E_(1a) to E_(1e) represent a nitrogen atom. In the case where two of E_(1a) to E_(1e) represent a nitrogen atom, preferably, two of E_(1a), E_(1d) and E_(1e) represent a nitrogen atom; more preferably E_(1a) and E_(1d), or E_(1a) and E_(1e) represent a nitrogen atom; and still more preferably, E_(1a) and E_(1d) represent a nitrogen atom.

The ring formed by E_(1f) to E_(1k) is a 5- or 6-membered aromatic hydrocarbon ring or heterocyclic ring, preferably a 6-membered ring, more preferably a 6-membered aromatic hydrocarbon ring. Specific examples of the ring formed by E_(1f) to E_(1k) include benzene, oxazole, thiazole, isoxazole, isothiazole, oxadiazole, thiadiazole, furan, thiophene, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrazine, pyrimidine, pyridazine and triazine. Among these, pyridine and benzene are preferred, and benzene is more preferred.

The ring formed by E_(1l) to E_(1q) is a 5- or 6-membered aromatic hydrocarbon ring or heterocyclic ring, preferably a 6-membered ring, still more preferably a 6-membered aromatic hydrocarbon ring. Specific examples of the ring formed by E_(1l) to E_(1q) include benzene, oxazole, thiazole, isoxazole, isothiazole, oxadiazole, thiadiazole, furan, thiophene, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrazine, pyrimidine, pyridazine and triazine. Among these, pyridine and benzene are preferred, and benzene is more preferred.

Each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent. The substituent is preferably a group selected from Substituent Group Z.

Specific examples of Substituent Group Z include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an amino group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a heteroarylthio group, a sulfonyl group, a sulfinyl group, a ureido group, a phosphoric acid amido group, a hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group except for heteroaryl group, a silyl group, a silyloxy group and a deuterium atom. These substituents may further be substituted with other substituents.

Here, the alkyl group is preferably an alkyl group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 10, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-octadecyl, n-hexadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, 1-adamantyl and trifluoromethyl.

The alkenyl group is preferably an alkenyl group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, and examples thereof include vinyl, allyl, 1-propenyl, 1-isopropenyl, 1-butenyl, 2-butenyl and 3-pentenyl.

The alkynyl group is preferably an alkynyl group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, and examples thereof include ethynyl, propargyl, 1-propynyl and 3-pentynyl.

The aryl group indicates an aromatic hydrocarbon monoradical. In the case where the aryl group is substituted, preferred examples of the substituent include a fluoro group, a hydrocarbon substituent, a heteroatom-substituted hydrocarbon substituent and a cyano group. The aryl group is preferably an aryl group having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, and examples thereof include phenyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, 2,6-xylyl, p-cumenyl, mesityl, naphthyl and anthranyl.

The heteroaryl group indicates an aromatic heterocyclic monoradical. In the case where the heteroaryl group is substituted, preferred examples of the substituent include a fluoro group, a hydrocarbon substituent, a heteroelement-substituted hydrocarbon substituent and a cyano group. Examples of the heterocyclic group include imidazolyl, pyrazolyl, pyridyl, pyrazyl, pyrimidyl, triazinyl, quinolyl, isoquinolinyl, pyrrolyl, indolyl, furyl, thienyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, carbazolyl and azepinyl.

The amino group is preferably an amino group having a carbon number of 0 to 30, more preferably from 0 to 20, still more preferably from 0 to 10, and examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino and ditolylamino.

The alkoxy group is preferably an alkoxy group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 10, and examples thereof include methoxy, ethoxy, butoxy and 2-ethylhexyloxy.

The aryloxy group is preferably an aryloxy group having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, and examples thereof include phenyloxy, 1-naphthyloxy and 2-naphthyloxy.

The heterocyclic oxy group is preferably a heterocyclic oxy having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy and quinolyloxy.

The acyl group is preferably an acyl group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 12, and examples thereof include acetyl, benzoyl, formyl and pivaloyl.

The alkoxycarbonyl group is preferably an alkoxycarbonyl group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 12, and examples thereof include methoxycarbonyl and ethoxycarbonyl.

The aryloxycarbonyl group is preferably an aryloxycarbonyl group having a carbon number of 7 to 30, more preferably from 7 to 20, still more preferably from 7 to 12, and examples thereof include phenyloxycarbonyl.

The acyloxy group is preferably an acyloxy group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, and examples thereof include acetoxy and benzoyloxy.

The acylamino group is preferably an acylamino group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 10, and examples thereof include acetylamino and benzoylamino.

The alkoxycarbonylamino group is preferably an alkoxycarbonylamino group having a carbon number of 2 to 30, more preferably from 2 to 20, still more preferably from 2 to 12, and examples thereof include methoxycarbonylamino.

The aryloxycarbonylamino group is preferably an aryloxycarbonylamino group having a carbon number of 7 to 30, more preferably from 7 to 20, still more preferably from 7 to 12, and examples thereof include phenyloxycarbonylamino.

The sulfonylamino group is preferably a sulfonylamino group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include methanesulfonylamino and benzenesulfonylamino.

The sulfamoyl group is preferably a sulfamoyl group having a carbon number of 0 to 30, more preferably from 0 to 20, still more preferably from 0 to 12, and examples thereof include sulfamoyl, methylsulfamoyl, dimethylsulfamoyl and phenylsulfamoyl.

The carbamoyl group is preferably a carbamoyl group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl and phenylcarbamoyl.

The alkylthio group is preferably an alkylthio group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include methylthio and ethylthio.

The arylthio group is preferably an arylthio group having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, and examples thereof include phenylthio.

The heteroarylthio group is preferably a heteroarylthio group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio and 2-benzothiazolylthio.

The sulfonyl group is preferably a sulfonyl group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include mesyl, tosyl and trifluoromethanesulfonyl.

The sulfinyl group is preferably a sulfinyl group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include methanesulfinyl and benzenesulfinyl.

The ureido group is preferably a ureido group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include ureido, methylureido and phenylureido.

The phosphoric acid amido group is preferably a phosphoric acid amido group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 12, and examples thereof include diethylphosphoric acid amido and phenylphosphoric acid amido.

Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom and iodine atom.

The heterocyclic group except for heteroaryl group is preferably a heterocyclic group having a carbon number of 1 to 30, more preferably from 1 to 12. The heteroatom is, for example, nitrogen atom, oxygen atom or sulfur atom. Specific examples of the heterocyclic group include piperidyl, morpholino and pyrrolidyl.

The silyl group is preferably a silyl group having a carbon number of 3 to 40, more preferably from 3 to 30, still more preferably from 3 to 24, and examples thereof include trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethyl-tert-butylsilyl, dimethylphenylsilyl, diphenyl-tert-butylsilyl, triphenylsilyl, tri-1-naphthylsilyl and tri-2-naphthylsilyl.

The silyloxy group is preferably a silyloxy group having a carbon number of 3 to 40, more preferably from 3 to 30, still more preferably from 3 to 24, and examples thereof include trimethylsilyloxy and triphenylsilyloxy.

Each of R_(1a) to R_(1i) is preferably a hydrogen atom, a hydrocarbon substituent (preferably an alkyl group, a cycloalkyl group or an aryl group), a cyano group, a fluoro group, OR_(2a), SR_(2a), NR_(2a)R_(2b), BR_(2a)R_(2b) or SiR_(2a)R_(2b)R_(2c). Each of R_(2a) to R_(2c) is independently a hydrocarbon substituent or a hydrocarbon substituent substituted with a heteroatom. Two of R_(1a) to R_(1i) and R_(2a) to R_(2c) may combine with each other to form a saturated or unsaturated, aromatic or non-aromatic ring.

At least one of R_(1a) to R_(1i) is preferably an aryl group having a dihedral angle of 70° or more with respect to the mother structure, more preferably a substituent represented by the following formula ss-1, still more preferably a 2,6-disubstituted aryl group, and it is most preferred that R_(1b) is a 2,6-disubstituted aryl group.

(In formula ss-1, each of Ra, Rb and Rc independently represents a hydrogen atom, an alkyl group or an aryl group, and the number of Rc is from 0 to 3).

The alkyl group represented by Ra, Rb and Rc is preferably an alkyl group having a carbon number of 1 to 30, more preferably from 1 to 20, still more preferably from 1 to 10, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-octadecyl, n-hexadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, 1-adamantyl and trifluoromethyl. Among these, a methyl group and an isopropyl group are preferred.

The aryl group represented by Ra, Rb and Rc is preferably an aryl group having a carbon number of 6 to 30, more preferably from 6 to 20, still more preferably from 6 to 12, and examples thereof include phenyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, 2,6-xylyl, p-cumenyl, mesityl, naphthyl and anthranyl. Among these, a phenyl group, a 2,6-xylyl group and a mesityl group are preferred, and a phenyl group is more preferred.

At least one of Ra and Rb is preferably selected from an alkyl group and an aryl group; more preferably, at least one of Ra and Rb is selected from an alkyl group; still more preferably, both Ra and Rb are an alkyl group; and most preferably, both Ra and Rb are a methyl group or an isopropyl group.

The 2,6-disubstituted aryl group is preferably a 2,6-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a 2,6-diisopropylphenyl group, a 2,4,6-diisopropylphenyl group, a 2,6-dimethyl-4-phenylphenyl group, a 2,6-dimethyl-4-(2,6-dimethylpyridin-4-yl)phenyl group, a 2,6-diphenylphenyl group, a 2,6-diphenyl-4-isopropylphenyl group, a 2,4,6-triphenylphenyl group, a 2,6-diisopropyl-4-(4-isopropylphenyl)phenyl group, a 2,6-diisopropyl-4-(3,5-dimethylphenyl)phenyl group, a 2,6-diisopropyl-4-(pyridin-4-yl)phenyl group or a 2,6-di-(3,5-dimethylphenyl)phenyl group,

The number of Rc is preferably 0 or 1. Each Rc may be the same as or different from every other Rc.

At least one of R_(1a) and R_(1b) is preferably an electron-donating group; more preferably, R_(1a) is an electron-donating group; and still more preferably, R_(1a) is a methyl group.

The hydrocarbon substituent indicates a monovalent or divalent, chain, branched or cyclic substituent composed of only a carbon atom and a hydrogen atom.

Examples of the monovalent hydrocarbon substituent include an alkyl group having a carbon number of 1 to 20; an alkyl group having a carbon number of 1 to 20 substituted with one or more groups selected from an alkyl group having a carbon number of 1 to 20, a cycloalkyl group having a carbon number of 3 to 8 and an aryl group; a cycloalkyl group having a carbon number of 3 to 8; a cycloalkyl group having a carbon number of 3 to 8 substituted with one or more groups selected from an alkyl group having a carbon number of 1 to 20, a cycloalkyl group having a carbon number of 3 to 8 and an aryl group; an aryl group having a carbon number of 6 to 18; and an aryl group substituted with one or more groups selected from an alkyl group having a carbon number of 1 to 20, a cycloalkyl group having a carbon number of 3 to 8 and an aryl group.

Examples of the divalent hydrocarbon group include —CH₂—, —CH₂—, —CH₂CH₂CH₂— and 1,2-phenylene group.

The metal in the phosphorescent metal complex for use in the present invention is preferably a metal having an atomic weight of 40 or more, which belongs to Groups 8 to 10 of the periodic table. Also, the metal is preferably a nonradioactive metal. The metal in the phosphorescent metal complex for use in the present invention is preferably any one of Re, Ru, Os, Rh, Ir, Pd, Pt, Cu and Au, more preferably Os, Ir or Pt, still more preferably Ir or Pt, and in view of high luminous efficiency, high complex stability and control of the carrier balance in the hole/electron transporting inside of the light emitting layer, most preferably Ir.

In the present invention, the metal complex composed of a ligand in the formula may be configured by a primary ligand or its tautomer and an auxiliary ligand or its tautomer, or all ligands of the metal complex may be composed of only a partial structure represented by the primary ligand or its tautomer.

If desired, the metal complex may have, as an auxiliary ligand, a ligand (sometimes referred to as a coordination compound) known as a so-called ligand to one skilled in the art and used for the formation of conventionally known metal complexes.

From the standpoint of successfully obtaining the effects described in the present invention, the complex is preferably composed of one kind or two kinds of ligands, more preferably one kind of a ligand. In view of easiness of synthesis when introducing a reactive group into the complex molecule, it is also preferred that he complex is composed of two kinds of ligands.

As for the ligand used in conventionally known metal complexes, various ligands are known, but examples thereof include ligands described in H. Yersin, Photochemistry and Photophysics of Coordination Compounds, Springer-Verlag (1987), and Akio Yamamoto, Yuki Kinzoku Kagaku-Kiso to Oyo-(Organic Metal Chemistry-Basic and Application), Shokabo (1982) (for example, a halogen ligand (preferably chlorine ligand), a cyano ligand, a phosphine ligand, a nitrogen-containing heteroaryl ligand (e.g., bipyridyl, phenanthroline), and a diketonate ligand (e.g., acetylacetone)). Diketones and picolinic acid derivatives are preferred.

Specific examples of the auxiliary ligand are set forth below, but the present invention is not limited thereto.

(M₁ represents a metal atom having an atomic weight of 40 or more, and each of Rx, Ry and Rz independently represents a hydrogen atom or a substituent).

The monoanionic bidentate ligand represented by any one of formulae (A1) to (A4) is preferably a monoanionic bidentate ligand represented by formula (A1) or (A3).

The monoanionic bidentate ligand represented by formula (A1) or (A3) is preferably a monoanionic bidentate ligand represented by formula (A1-1) or (A3-1) or represented by formula (A1-2) or (A3-2).

(In formulae (A1-1), (A3-1), (A1-2) and (A3-2), each of E_(1f) to E_(1q) independently represents a carbon atom or a heteroatom, each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), and each of the frameworks represented by formulae (A1-1), (A3-1), (A1-2) and (A3-2) has a structure with 18 π-electrons in total).

In formulae (A1-1), (A3-1), (A1-2) and (A3-2), the definitions of E_(1f) to E_(1q) and R_(1a) to are the same as those of E_(1f) to E_(1q) and R_(1a) to R_(1i) in formulae (A1) and (A3), and the preferred ranges are also the same.

The monoanionic bidentate ligand represented by formula (A1-1), (A3-1), (A1-2) or (A3-2) is preferably a monoanionic bidentate ligand represented by formula (A1-3) or (A3-3):

(In formulae (A1-3) and (A3-3), each of E_(1f) to E_(1k) independently represents a carbon atom or a heteroatom, each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), and each of the frameworks represented by formulae (A1-3) and (A3-3) has a structure with 18 π-electrons in total).

In formulae (A1-3) and (A3-3), the definitions of E_(1f) to E_(1q) and R_(1a) to R_(1i) are the same as those of E_(1f) to E_(1q) and R_(1a) to R_(1i) in formulae (A1-1), (A3-1), (A1-2) and (A3-2), and preferred ranges are also the same.

The phosphorescent metal complex containing a monoanionic bidentate ligand represented by formula (A1-3) or (A3-3) and a metal having an atomic weight of 40 or more is preferably an iridium complex represented by formula (A9):

(In formula (9), each of R_(1a) to R_(1i) independently represents a hydrogen atom or a substituent, provided that at least one of R_(1a) to R_(1i) represents a group represented by formula (I), X—Y represents at least one monoanionic bidentate ligand selected from (1-1) to (1-14), and n represents an integer of 1 to 3).

In formula (A9), preferred ranges of R_(1a) to R_(1i) are the same as preferred ranges of R_(1a) to R_(1i) in formula (A1).

X—Y represents an auxiliary ligand, and n represents an integer of 1 to 3 and is preferably n=3. As for the auxiliary ligand, specifically, the same ligands as described above can be suitably used, and an acetylacetonate ligand and a substituted acetylacetonate ligand analog are preferred.

From the standpoint of easiness of synthesis, n is preferably 3, but it is also preferred in view of cost that n is 1 or 2, because the ligand can be replaced by an inexpensive auxiliary ligand.

The metal complex represented by formula (A9) is preferably a metal complex represented by formula (A10). In the formula, R_(1e) is a substituent represented by formula (I).

More specifically, formulae (A1) and (A3) are preferably the following structures. Among these, X-1, X-4, X-32, X-33, X-38, X-39, X-46, X-51, X-52, X-53, X-55, X-56, X-57, X-58, X-59, X-62, X-63, X-64, X-66, X-67 and X-68 are more preferred, and X-46, X-52, X-53, X-56, X-57, X-58, X-62 and X-66 are most preferred.

R^(1a) to R^(1i) have the same meanings as in formula (A1), and it is preferred that all are a hydrogen atom.

The phosphorescent metal complex containing a monoanionic bidentate ligand represented by formulae (A1) to (A4) and a metal having an atomic weight of 40 or more can be synthesized by various methods such as methods described in US2007/0190359 and US2008/0297033.

For example, a ligand or a dissociation product thereof and a metal compound are reacted with or without a solvent (for example, a halogen-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, a ketone-based solvent, a nitrile-based solvent, an amide-based solvent, a sulfone-based solvent, a sulfoxide-based solvent or water) in the presence or absence of a base (various inorganic or organic bases, for example, sodium methoxide, tert-butoxy potassium, triethylamine or potassium carbonate) at not higher than room temperature or under heating (in addition to normal heating, microwave heating is also effective), whereby the complex can be obtained. Specifically, XM-64 can be synthesized starting from 7-methyl-imidazophenanthridine according to the synthesis method described in US2007/0190359, paragraphs [0132] to [0134]. Also, XM-63 can be synthesized according to the synthesis method described in US2008/0297033, paragraphs [0281] to [0287].

In the present invention, the metal complex having a group represented by formula (I) is not limited in its use and may be contained in any layer within the organic layer. The layer into which the metal complex having a group represented by formula (I) is introduced may be any one of a light emitting layer, a hole injection layer, a hole transporting layer, an electron transporting layer, an electron injection layer, an exciton blocking layer and a charge blocking layer.

The present invention also relates to a composition containing the metal complex having a group represented by formula (I). By using a composition containing a metal complex having a saturated 5- to 8-membered ring-containing group, an organic electroluminescence device more excellent in the external quantum efficiency can be obtained.

In the present invention, in order to more reduce the change in chromaticity at high-temperature driving, the metal complex having a group represented by formula (I) is preferably incorporated into a light emitting layer.

The present invention also related to a light emitting layer containing the metal complex having a group represented by formula (I).

In the case of incorporating the metal complex having a group represented by formula (I) into a light emitting layer, the metal complex is preferably contained in an amount of 0.1 to 50 mass %, more preferably from 1 to 50 mass %, still more preferably from 2 to 40 mass %, based on the total mass of the light emitting layer.

Also, in the case of incorporating the metal complex having a group represented by formula (I) into a layer other than a light emitting layer, the metal complex is preferably contained in an amount of 0.1 to 100 mass %, more preferably from 10 to 100 mass %, still more preferably from 30 to 100 mass %.

[Organic Electroluminescence Device]

The device of the present invention is described in detail below.

The organic electroluminescence device of the present invention is an organic electroluminescence device including a substrate having thereon a pair of electrodes and at least one organic layer between the electrodes, the organic layer containing a light emitting layer,

wherein any one layer of the organic layer contains a meal complex having a group represented by formula (I).

In the organic electroluminescence device of the present invention, the light emitting layer is an organic layer, and the device may have a plurality of organic layers.

In view of property of the luminescence device, at least one electrode of the anode and the cathode is preferably transparent or translucent.

FIG. 1 shows one example of the configuration of the organic electroluminescence device of the present invention. In the organic electroluminescence device 10 of the present invention shown in FIG. 1, a light emitting layer 6 is sandwiched between an anode 3 and a cathode 9 on a supporting substrate 12. More specifically, a hole injection layer 4, a hole transporting layer 5, the light emitting layer 6, a hole blocking layer 7 and an electron transporting layer 8 are stacked in this order between the anode 3 and the cathode 9.

<Configuration of Organic Layer>

The layer configuration of the organic layer is not particularly limited and may be appropriately selected according to the use and purpose of the organic electroluminescence device but is preferably formed on the transparent electrode or back plate. In this case, the organic layer is formed on the front surface or one surface of the transparent electrode or back plate.

The shape, size, thickness and the like of the organic layer are not particularly limited and may be appropriately selected according to the purpose.

Specific examples of the layer configuration include the following configurations, but the present invention is not limited thereto.

-   -   Anode/hole transporting layer/light emitting layer/electron         transporting layer/cathode     -   Anode/hole transporting layer/light emitting layer/blocking         layer/electron transporting layer/cathode     -   Anode/hole transporting layer/light emitting layer/blocking         layer/electron transporting layer/electron injection         layer/cathode     -   Anode/hole injection layer/hole transporting layer/light         emitting layer/blocking layer/electron transporting         layer/cathode     -   Anode/hole injection layer/hole transporting layer/light         emitting layer/blocking layer/electron transporting         layer/electron injection layer/cathode

The device configuration, substrate, cathode and anode of an organic electroluminescence device are described in detail, for example, in JP-A-2008-270736, and the matters described therein can be applied to the present invention.

<Substrate>

The substrate used in the invention is preferably a substrate which causes neither scattering nor damping of light emitted from the organic layer. When the substrate is made from an organic material, it is preferable that the organic material has excellent heat resistance, dimensional stability, solvent resistance, electrical insulation and workability.

<Anode>

The anode is usually sufficient if it has a function as an electrode of supplying a hole to the organic layer. The shape, structure, size and the like thereof are not particularly limited, and the anode material may be appropriately selected from known electrode materials according to the use or purpose of the luminescence device. As described above, the anode is usually provided as a transparent anode.

<Cathode>

The cathode is usually sufficient if it has a function as an electrode of injecting an electron in the organic layer. The shape, structure, size and the like thereof are not particularly limited, and the cathode material may be appropriately selected from known electrode materials according to the use or purpose of the luminescence device.

As for the substrate, the anode and the cathode, the matters described in JP-A-2008-270736, paragraphs [0070] to [0089] can be applied to the present invention.

<Organic Layer>

The organic layer for use in the present invention is described below.

—Formation of Organic Layer—

In the organic electroluminescence device of the present invention, each organic layer may be suitably formed by any of a dry deposition method such as vapor deposition and sputtering, a transfer method, a printing method and the like.

(Light Emitting Layer)

<Light Emitting Material>

The light emitting material for use in the present invention is preferably a metal complex having a group represented by formula (I).

The light emitting material in the light emitting layer is generally contained in the light emitting layer, based on the mass of all compounds forming the light emitting layer, in an amount of 0.1 to 50 mass %, and in view of durability and external quantum efficiency, preferably in an amount of from 1 to 50 mass %, still more preferably from 2 to 40 mass %.

The thickness of the light emitting layer is not particularly limited but usually, the thickness is preferably from 2 to 500 nm, and in view of external quantum efficiency, more preferably from 3 to 200 nm, still more preferably from 5 to 100 nm.

In the device of the present invention, the light emitting layer may be composed of only a light emitting material or may have a mixed layer configuration of a host material and a light emitting material. The light emitting material may be either a fluorescent material or a phosphorescent material and as for the dopant, one kind of a dopant or two or more kinds of dopants may be used. The host material is preferably a charge transport material. As for the host material, one kind of a host material or two or more kinds of host materials may be used, and examples of this configuration include a configuration where an electron transporting host material and a hole transporting host material are mixed. Also, the light emitting layer may contain a material having no charge transport property and being incapable of producing luminescence.

Furthermore, the light emitting layer may be a single layer or a multilayer composed of two or more layers. In the case of a plurality of light emitting layers, the metal complex having a group represented by formula (I) may be contained in two or more light emitting layers. Also, respective light emitting layers may produce luminescence in different colors.

As regards the composition of the present invention, for example, the above-described components constituting the light emitting layer may be added to the light emitting material having a substituent represented by formula (1) of the present invention. It is also preferred to further add a compound represented by formula (VI) described later.

<Host Material>

Examples of the host material contained in the light emitting layer include a compound having a carbazole structure, a compound having an azacarbazole structure, a compound having an indole structure, a compound having an azaindole structure, a compound having a diarylamine structure, a compound having a pyridine structure, a compound having a pyrazine structure, a compound having a triazine structure, a compound having an arylsilane structure, and the materials exemplified later in the paragraphs of hole injection layer, hole transporting layer, electron injection layer and electron transporting layer. Among these, a compound having a carbazole structure and a compound having an indole structure are preferred.

Examples thereof include pyrrole, indole, carbazole (including CBP (4,4′-di(9-carbazolyl)biphenyl)), azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic tertiary amine compounds, styrylamine compounds, porphyrin compounds, polysilane compounds, poly(N-vinylcarbazole), aniline copolymers, thiophene oligomers, oligomers of conductive polymers like polythiophene, organic silanes, carbon film, pyridine, pyrimidine, triazine, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorelenylidenemethane, distyrylpyrazine, fluoro-substituted aromatic compounds, tetracarboxylic acid anhydrides of condensed aromatic ring compounds such as naphthalene and perylene, phthalocyanine, various kinds of metal complexes, typified by metal complexes of 8-quinolinol derivatives and metal complexes whose ligands are metallo-phthalocyanines, benzoxazole or benzothiazole molecules, and derivatives of the above-recited metal complexes (e.g. those replaced with substituents or those condensed with other rings).

In view of color purity, luminous efficiency and drive durability, the lowest triplet excitation energy (T₁ energy) of the host material in the light emitting layer for use in the present invention is preferably higher than the T₁ energy of the phosphorescent material.

In the present invention, the content of the host compound is not particularly limited but in view of luminous efficiency and drive voltage, the content is preferably from 15 to 95 mass % based on the mass of all compounds forming the light emitting layer.

The thickness of the light emitting layer is not particularly limited but usually, the thickness is preferably from 1 to 500 nm, more preferably from 5 to 200 nm, still more preferably from 10 to 100 nm.

(Fluorescent Material)

Examples of a fluorescent material usable in the invention include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styrylamine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidyne derivatives; various kinds of complexes typified by complexes of 8-quinolinol derivatives and complexes of pyrromethene derivatives, polymeric compounds such as polythiophene, polyphenylene and polyphenylenevinylene, and compounds like organic silane derivatives.

(Phosphorescent Material)

Examples of the phosphorescent material which can be used in the present invention include, other than the metal complex having a group represented by formula (1), phosphorescent compounds described in patent documents such as U.S. Pat. Nos. 6,303,238B1, 6,097,147, WO 00/57676, WO 00/70655, WO 01/08230, WO 01/39234A2, WO 01/41512A1, WO 02/02714A2, WO 02/15645A1, WO 02/44189A1, WO 05/19373A2, JP-A-2001-247859, JP-A-2002-302671, JP-A-2002-117978, JP-A-2003-133074, JP-A-2002-235076, JP-A-2003-123982, JP-A-2002-170684, EP 1211257, JP-A-2002-226495, JP-A-2002-234894, JP-A-2001-247859, JP-A-2001-298470, JP-A-2002-173674, JP-A-2002-203678, JP-A-2002-203679, JP-A-2004-357791, JP-A-2006-256999, JPA-2007-19462, JP-A-2007-84635 and JP-A-2007-96259. Examples of luminescent dopants which are far preferred among those compounds include the Ir complexes, the Pt complexes, the Cu complexes, the Re complexes, the W complexes, the Rh complexes, the Ru complexes, the Pd complexes, the Os complexes, the Eu complexes, the Tb complexes, the Gd complexes, the Dy complexes and the Ce complexes. Of these complexes, Ir complexes, the Pt complexes and the Re complexes are particularly preferable, notably Ir complexes, the Pt complexes and the Re complexes each having at least one kind of coordination bond selected from metal-carbon, metal-nitrogen, metal-oxygen and metal-sulfur coordinate bonds. In terms of luminous efficiency, durability under driving, chromaticity and so on, the Ir complexes, the Pt complexes and the Re complexes each having a polydentate ligand, including a tridentate ligand or higher, are preferred over the others.

The content of the phosphorescent material in the light emitting layer is preferably from 0.1 to 50 mass %, more preferably from 0.2 to 50 mass %, still more preferably from 0.3 to 40 mass %, and most preferably from 20 to 30 mass %, based on the total mass of the light emitting layer.

The content of the phosphorescent material (the metal complex having a group represented by formula (I) and/or a phosphorescent material used in combination) which can be used in the present invention is preferably from 0.1 to 50 mass %, more preferably from 1 to 40 mass %, and most preferably from 5 to 30 mass %, based on the total mass of the light emitting layer. In particular, within the range of 5 to 30 mass %, the chromaticity of luminescence of the organic electroluminescence device is small in the dependency on the concentration of the phosphorescent material added.

The organic electroluminescence device of the present invention most preferably contains at least one kind of the compound (I) (the metal complex having a group represented by formula (I)) in an amount of 5 to 30 mass % based on the total mass of the light emitting layer.

The organic electroluminescence device preferably further contains a hydrocarbon compound, and it is more preferred to contain a hydrocarbon compound in a light emitting layer.

The hydrocarbon compound is preferably a compound represented by the following formula (VI).

By appropriately using the compound represented by formula (VI) together with the light emitting material, the interaction between material molecules can be adequately controlled to make uniform the energy gap and interaction between adjacent molecules, whereby the drive voltage can be more lowered.

Also, the compound represented by formula (VI) for use in the organic electroluminescence device is excellent in chemical stability and less causes deterioration such as decomposition of the material during driving of the device, so that the organic electroluminescence device can be prevented from reduction in the efficiency or life due to decomposition of the material.

The compound represented by formula (VI) is described below.

In formula (VI), each of R₄, R₆, R₈, R₁₀ and X₄ to X₁₅ independently represents a hydrogen atom, an alkyl group or an aryl group.

The alkyl group represented by each of R₄, R₆, R₈, R₁₀ and X₄ to X₁₅ in the formula (VI) may have as a substituent an adamantane structure or an aryl structure, and the number of carbon atoms in the alkyl group is preferably from 1 to 70, far preferably from 1 to 50, further preferably from 1 to 30, still further preferably from 1 to 10, especially preferably from 1 to 6. And the most preferable alkyl groups are linear alkyl groups having 2 to 6 carbon atoms.

Examples of the alkyl group represented by each of R₄, R₆, R₈, R₁₀ and X₄ to X₁₅ in the formula (VI) include an n-C₅₀H₁₀₁ group, an n-C₃₀H₆₁ group, 3-(3,5,7-triphenyladamantane-1-yl)propyl group (number of carbon atoms: 31), a trityl group (number of carbon atoms: 19), 3-(adamantane-1-yl)propyl group (number of carbon atoms: 13), 9-decalyl group (number of carbon atoms: 10), a benzyl group (number of carbon atoms: 7), a cyclohexyl group (number of carbon atoms: 6), a n-hexyl group (number of carbon atoms: 6), an n-pentyl group (number of carbon atoms: 5), an n-butyl group (number of carbon atoms: 4), an n-propyl group (number of carbon atoms: 3), a cyclopropyl group (number of carbon atoms: 3), an ethyl group (number of carbon atoms: 2) and a methyl group (number of carbon atoms: 1).

The aryl group represented by each of R₄, R₆, R₈, R₁₀ and X₄ to X₁₅ in the formula (VI) may have as a substituent an adamantane structure or an alkyl structure, and the number of carbon atoms the aryl group has is preferably from 6 to 30, far preferably from 6 to 20, further preferably from 6 to 15, especially preferably from 6 to 10, the most preferably is 6.

Examples of the aryl group represented by each of R₄, R₆, R₈, R₁₀ and X₄ to X₁₅ in the formula (VI) include a 1-pyrenyl group (number of carbon atoms: 16), a 9-anthracenyl group (number of carbon atoms: 14), a 1-naphthyl group (number of carbon atoms: 10), a 2-natphthyl group (number of carbon atom: 10), a p-t-butylphenyl group (number of carbon atoms: 10), a 2-m-xylyl group (number of carbon atoms: 8), a 5-m-xylyl group (number of carbon atoms: 8), an o-tolyl group (number of carbon atoms: 7), a m-tolyl group (number of carbon atoms: 7), a p-tolyl group (number of carbon atoms: 7) and a phenyl group (number of carbon atoms: 6).

Although each of R₄, R₆, R₈ and R₁₀ in the formula (VI) may be either a hydrogen atom, or an alkyl group, or an aryl group, from the viewpoint that high glass transition temperatures are preferable, it is preferable that at least one of them is an aryl group, it is far preferable that at least two of them are aryl groups, and it is particularly preferable that 3 or 4 of them are aryl groups.

Although each of X₄ to X₁₅ in the formula (VI) may represent either a hydrogen atom, or an alkyl group, or an aryl group, it is preferable that each stands for a hydrogen atom or an aryl group, especially a hydrogen atom.

The organic electroluminescence devices are made using a vacuum deposition process or a solution coating process, and therefore, in terms of vacuum deposition suitability and solubility, the molecular weight of the compounds represented by the formula (VI) in the invention is preferably 2,000 or below, far preferably 1,200 or below, especially 1,000 or below. Also, from the viewpoint of vacuum deposition suitability, the molecular weight is preferably 250 or above, far preferably 350 or above, particularly preferably 400 or above. This is because, when the compounds have too low molecular weight, their vapor pressure becomes low and change from a vapor phase to a solid phase does not occur, and it is therefore difficult for the compounds to form organic layers.

The compound represented by the formula (VI) is preferably in solid phase at room temperature (25° C.), far preferably solid phase in a range from room temperature to 40° C., especially preferably solid phase in a range from room temperature to 60° C.

In the case of using the compound which, though represented by the formula (VI), is not in solid phase at room temperature, it is possible to form a solid phase at ordinary temperatures by combining the compound with other substances.

Uses of the compound represented by the formula (VI) are not limited, and the compound may be incorporated into any of the organic layers. The layer into which the compound represented by the formula (VI) in the invention is introduced is preferably a layer selected from a light emitting layer, a hole injection layer, a hole transporting layer, an electron transporting layer, an electron injection layer, an exciton block layer and a charge blocking layer, or a combination of two or more of these layers, far preferably a layer selected from the light emitting layer, the hole injection layer, the hole transporting layer, the electron transporting layer and the electron injection layer, or a combination of two or more of these layers, especially preferably a layer selected from the light emitting layer, the hole injection layer and the hole transporting layer, or a combination of at least two of these layers, the most preferably the light emitting layer.

When the compound represented by the formula (VI) is used in an organic layer, its content is required to be limited so as not to inhibit charge transportability, and therefore it is preferable from 0.1% to 70% by mass, far preferable from 0.1% to 30% by mass, especially preferable from 0.1% to 25% by mass.

When the compound represented by the formula (VI) is used in two or more organic layers, its content in each organic layer is preferably in the range specified above.

Only one kind of a compound represented by formula (VI) may be contained in any organic layer, or a plurality of kinds of compounds represented by formula (VI) may be contained in combination in an arbitrary ratio.

Specific examples of the hydrocarbon compound are illustrated below, but the present invention is not limited thereto.

The compound represented by the formula (VI) can be synthesized by appropriately combining adamantane or haloadamantane with haloalkane or alkylmagnesium halide (Grignard reagent). For instance, it is possible to provide coupling between haloadamantane and haloalkane by use of indium (Reference 1). Alternatively, it is possible to convert haloalkane into an alkylcopper reagent and further to couple the reagent to Grignard reagent of an aromatic compound (Reference 2). Further, the coupling of haloalkane can also be performed using an appropriate arylboric acid and a palladium catalyst (Reference 3).

Reference 1: Tetrahedron Lett. 39, 9557-9558 (1998)

Reference 2: Tetrahedron Lett. 39, 2095-2096 (1998)

Reference 3: J. Am. Chem. Soc. 124, 13662-13663 (2002)

The adamantane structure having an aryl group can be synthesized by appropriately combining adamantane or haloadamantane with the corresponding arene or haloarene.

Additionally, even when defined substituents undergo changes under certain synthesis conditions in those production methods or they are unsuitable for carrying out those methods, the intended compounds can be produced with ease by adopting e.g. methods for protecting and deprotecting functional groups (T. W. Greene, Protective Groups in Organic Synthesis, John Wiley & Sons Inc. (1981)). Further, it is also possible to change the order of reaction steps, including a substituent introduction step, as appropriate, if needed.

The thickness of the light emitting layer is not particularly limited but usually, the thickness is preferably from 1 to 500 nm, more preferably from 5 to 200 nm, still more preferably from 10 to 100 nm.

—Hole Injection Layer, Hole Transporting Layer—

The hole injection layer and the hole transporting layer are a layer having a function of receiving a hole from the anode or anode side and transporting it to the cathode side.

—Electron Injection Layer, Electron Transporting Layer—

The electron injection layer and the electron transporting layer are a layer having a function of receiving an electron from the cathode or cathode side and transporting it to the anode side.

As regards the hole injection layer, hole transporting layer, electron injection layer and electron transporting layer, the matters described in JP-A-2008-270736, paragraphs [0165] to [0167] can be applied to the present invention.

—Hole Blocking Layer—

The hole blocking layer is a layer having a function of blocking the holes transported from an anode side to the light emitting layer from passing on through to the cathode side. In the invention, the hole blocking layer can be provided as an organic layer adjacent to the light emitting layer in the cathode side.

Examples of an organic compound which forms the hole blocking layer include aluminum complexes such as aluminum(III) bis(2-methyl-8-quinolinato) 4-phenylphenolate (abbreviated to BAlq), triazole derivatives, and phenanthroline derivatives such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated to BCP).

The thickness of the hole blocking layer is preferably from 1 nm to 500 nm, far preferably from 5 nm to 200 nm, further preferably from 10 nm to 100 nm.

The hole blocking layer may have either a single-layer structure made up of one or more than one material as recited above or a multiple-layer structure made up of two or more layers which are identical or different in composition.

—Electron Blocking Layer—

The electron blocking layer is a layer having a function of preventing the electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the invention, the electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.

As the examples of the compounds constituting the electron blocking layer, for instance, the hole transporting materials described above can be applied.

The thickness of the electron blocking layer is preferably from 1 nm to 500 nm, more preferably from 5 nm to 200 nm, still more preferably from 10 nm to 100 nm. The electron blocking layer may have a single layer structure composed of one or more of the above materials or may be a multilayer structure composed of two or more layers having the same composition or different compositions.

<Protective Layer>

In the present invention, the entire organic EL device may be protected by a protective layer.

As for the protective layer, the matters described in JP-A-2008-270736, paragraphs [0169] and [0170] can be applied to the present invention.

<Sealing Container>

The device of the present invention may be entirely sealed using a sealing container.

As for the sealing container, the matters described in JP-A-2008-270736, paragraph [0171] can be applied to the present invention.

(Drive)

Luminescence of the organic electroluminescence device of the present invention can be obtained by applying a DC (if desired, an AC component may be contained) voltage (generally from 2 to 15 volts) or a DC current between the anode and the cathode.

As for the driving method of the organic electroluminescence device of the present invention, the driving methods described, for example, in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234685, JP-A-8-241047, Japanese Patent 2784615, and U.S. Pat. Nos. 5,828,429 and 6,023,308 can be applied.

The present organic electroluminescence devices can be heightened in light extraction efficiency by utilizing various publicly-known improvements. For instance, it is possible to improve light extraction efficiency and increase external quantum efficiency by working on the substrate's surface profile (e.g. forming a pattern of microscopic asperities on the substrate's surface), or by controlling refractive indices of the substrate, the ITO layer and the organic layers, or by controlling thicknesses of the substrate, the ITO layer and the organic layers, or so on.

The luminescence device of the present invention may be in a so-called top emission system of collecting light from the anode side.

The present organic EL devices may have resonator structure. For instance, each device has on a transparent substrate a multilayer film mirror made up of a plurality of laminated films that have different refractive indices, a transparent or translucent electrode, a light emitting layer and a metal electrode which are superposed on top of each other. Reflections of light produced in the light emitting layer occur repeatedly between the multilayer film mirror and the metal electrode which function as reflector plates, thereby producing resonance.

In another aspect, the transparent or translucent electrode and the metal electrode function as reflector plates, respectively, on the transparent substrate, and reflections of light produced in the light emitting layer occur repeatedly between the reflector plates, thereby producing resonance.

In order to form a resonance structure, the optical distance determined from effective refractive indices of the two reflector plates, and refractive indices and thicknesses of each layers sandwiched between the two reflector plates are adjusted to have optimum values for achieving the desired resonance wavelength. The calculating formula in the first aspect case is described in JP-A-9-180883, and that in the second aspect case is described in JP-A-2004-127795.

(Use of Luminescence Device of the Present Invention)

The present luminescence devices can be used suitably for light luminous apparatus, pixels, indication devices, displays, backlights, electrophotographic devices, illumination light sources, recording light sources, exposure light sources, readout light sources, sign, billboards, interior decorations or optical communications, especially preferably for devices driven in a region of high-intensity luminescence, such as illumination apparatus and display apparatus.

Next the present light luminous apparatus is explained by reference to FIG. 2.

The present light luminous apparatus incorporates any one of the present organic electroluminescence devices.

FIG. 2 is a cross-sectional diagram schematically showing one example of the present light luminous apparatus.

The light luminous apparatus 20 in FIG. 2 includes a transparent substrate 2 (supporting substrate), an organic electroluminescence device 10, a sealing enclosure 16 and so on.

The organic electroluminescence device 10 is formed by stacking on the substrate 2 an anode 3 (first electrode), an organic layer 11 and a cathode 9 (second electrode) in the order of mention. In addition, a protective layer 12 is superposed on the cathode 9, and on the protective layer 12 a sealing enclosure 16 is further provided via an adhesive layer 14. Incidentally, part of each of the electrodes 3 and 9, a diaphragm and an insulating layer are omitted in FIG. 2.

Herein, a light cure adhesive such as epoxy resin, or a thermosetting adhesive can be used for the adhesive layer 14. Alternatively, a thermosetting adhesive sheet may be used as the adhesive layer 14.

The present light emission apparatus has no particular restrictions as to its uses, and specifically, it can be utilized e.g. as not only illumination apparatus but also display apparatus of a television set, a personal computer, a mobile phone, an electronic paper or the like.

The illumination apparatus according to an embodiment of the present invention is described below by referring to FIG. 3.

The illumination apparatus 40 according to an embodiment of the present invention contains, as shown in FIG. 3, the above-described organic electroluminescence device 10 and a light scattering member 30. More specifically, the illumination apparatus 40 is configured such that the substrate 2 of the organic electroluminescence device 10 and the light scattering member 30 are in contact with each other.

The light scattering member 30 is not particularly limited as long as it can scatter light, but in FIG. 3, a member obtained by dispersing fine particles 32 in a transparent substrate 31 is used. Suitable examples of the transparent substrate 31 include a glass substrate, and suitable examples of the fine particle 32 include a transparent resin fine particle. As the glass substrate and the transparent resin fine particle, a known product can be used for both. In such an illumination apparatus 40, when light emitted from the organic electroluminescence device 10 is incident on the light incident surface 30A of the scattering member 30, the incident light is scattered by the light scattering member and the scattered light is output as illuminating light from the light output surface 30B.

EXAMPLES

The present invention is described in greater detail below by referring to Examples, but the embodiment of the present invention is not limited thereto.

[Synthesis of Compound 2]

Compound 2 was synthesized according to the following scheme.

In a nitrogen atmosphere, 2.1 equivalents of Ligand 1 and 1 equivalent of iridium chloride n-hydrate were reacted in a mixed solvent of 2-ethoxyethanol/H₂O (=3:1) by refluxing at the boiling point for 5 hours to obtain Chlorine Linked Complex 2. In 2-ethoxyethanol, Chlorine Linked Complex 2 and 3 equivalents of acetylacetone were refluxed at the boiling point for 3 hours in the co-presence of sodium carbonate to obtain acac Complex 3. Subsequently, acac Complex 3 and 1.5 equivalents of Ligand 1 were reacted in glycerol at 200° C., whereby the objective Compound 2 was synthesized.

[Synthesis of Compound 157]

Compound 157 was synthesized according to the following scheme.

From 1 to 1.2 equivalents of a base such as lithium diisopropylamide, potassium tert-butoxide and sodium hydride was added to an N,N-dimethylformamide solution of Compound (A) at 0° C. to room temperature, and the reaction was allowed to proceed at 0° C. to room temperature for about 30 minutes. Thereto, from 1.5 to 4 equivalents of methyl iodide was added and after monomethylation through reaction at room temperature for about 30 minutes, from 1 to 1.2 equivalents of the base described above and excess methyl iodide were again reacted under the same conditions to obtain Dimethyl Substitution (B) in a yield of 70 to 99%.

In the process of obtaining Compound (C) from Compound (B), Compound (B) as well as from 2 to 3 equivalents of sodium carbonate and from 0.05 to 0.2 equivalents of tetrakis(triphenylphosphine)palladium(0) were dissolved in a toluene/ethanol/water mixed solvent or a 1,2-dimethoxyethane/water mixed solvent, and the solution was heated to a temperature of 70° C. to heat-refluxing temperature and stirred for 2 to 24 hours, whereby Compound (C) was synthesized.

In the process of obtaining Compound 157 from Compound (C), Compound (C) and from 1 to 1.5 equivalents of platinum chloride were dissolved in benzonitrile, and the solution was heated to a temperature of 130° C. to heat-refluxing temperature (boiling point of benzonitrile: 191° C.) and stirred for 30 minutes to 4 hours, whereby the compound was synthesized. Compound 157 was purified by recrystallization using chloroform or ethyl acetate, silica gel column chromatography, sublimation purification or the like.

Incidentally, metal complexes represented by formulae (A1) to (A4) were also synthesized by various techniques, for example, the methods described in U.S. Patent Application Publication 2007/0190359 and U.S. Patent Application Publication 2008/0297033. Furthermore, 11 and 12 can be synthesized using the synthesis method described in JP-A-2009-102533, page 189, paragraphs 288 to 302.

Example 1 Example 1-1

A 0.5 mm-thickness 2.5 cm-square glass substrate having thereon ITO film (produced by GEOMATEC Corporation, surface resistance: 10 Ω/sq.) was placed in a cleaning vessel and subjected to ultrasonic cleaning in 2-propanol and then to a UV-ozone treatment for 30 minutes. On this transparent anode (ITO film), the following organic layers (organic compound layers) were sequentially deposited by the vacuum deposition method.

Unless otherwise indicated, the vapor deposition rate in Examples of the present invention is 0.2 nm/sec. The vapor deposition rate was measured using a crystal oscillator. In the following, the film thickness is a value as measured also by using a crystal oscillator.

After placing the cleaned ITO substrate in a vapor deposition apparatus, copper phthalocyanine was deposited to a thickness of 10 nm (first layer), and NPD (N,N′-di-α-naphthyl-N,N′-diphenyl)-benzidine) was deposited thereon to a thickness of 40 nm (second layer). Furthermore, H-1 and Compound A-1 of the present invention in a ratio of 95:5 (by mass) were deposited thereon to a thickness of 30 nm (third layer/light emitting layer), and BAlq [aluminum bis-(2-methyl-8-quinolinato)-4-phenylphenolate] was deposited thereon to a thickness of 40 nm (fourth layer). Thereafter, lithium fluoride was deposited thereon to a thickness of 3 nm, and aluminum was further deposited to a thickness of 60 nm. The obtained laminate was placed in an argon gas-purged glove box without exposing to the atmosphere and then encapsulated using a stainless steel-made sealing can and an ultraviolet curable adhesive (XNR5516HV, produced by Nagase-Ciba Ltd.) to produce the organic EL device of Example 1-1. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from Compound A-1 of the present invention was obtained.

Examples 1-2 to 1-5 and Comparative Examples 1-1 to 1-5

The devices of Examples 1-2 to 1-5 and Comparative Examples 1-1 to 1-5 were produced in the same manner as in Example 1-1 except for changing the materials used in Example 1-1 to the materials shown in Table 1. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

(Measurement of Drive Voltage)

Each of the organic electroluminescence devices of Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-5 was set in an emission spectrum-measuring system (ELS1500) manufactured by Shimadzu Corporation, and the applied voltage at a luminance of 100 cd/m² was measured.

(Evaluation of Drive Durability)

Each of the organic electroluminescence devices of Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-5 was set in OLED Test System Model ST-D manufactured by Tokyo System Development Co., Ltd. and driven under the conditions of a constant-current mode and an initial luminance of 1,000 cd/m², and the half-luminance time was measured.

(Evaluation of External Quantum Efficiency)

With respect to the organic electroluminescence devices of Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-5, a DC voltage was applied to the EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., and the external quantum efficiency (%) was calculated from the frontal luminance at 100 cd/m²,

(Evaluation of Chromaticity)

A DC voltage was applied to obtain a luminance of 1,000 cd/m², and the emission spectrum was measured by an emission spectrum-measuring system (ELS1500) manufactured by Shimadzu Corporation to calculate the chromaticity (CIE chromaticity).

TABLE 1 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-1 H-1 7.6 13.8 100 (0.61, 0.38) (0.65, 0.33) Example 1-1 Comparative B-2 H-1 8.4 14.0 106 (0.65, 0.32) (0.68, 0.29) Example 1-2 Comparative B-3 H-1 7.3 11.6 76 (0.50, 0.49) (0.53, 0.45) Example 1-3 Comparative B-4 H-1 7.1 10.1 56 (0.39, 0.56) (0.46, 0.50) Example 1-4 Comparative B-5 H-1 7.3 14.6 82 (0.41, 0.57) (0.44, 0.52) Example 1-5 Example 1-1 A-1 H-1 7.4 14.4 125 (0.60, 0.36) (0.61, 0.36) Example 1-2 A-2 H-1 8.2 14.9 136 (0.66, 0.33) (0.65, 0.32) Example 1-3 A-3 H-1 7.2 12.7 87 (0.51, 0.49) (0.51, 0.48) Example 1-4 A-4 H-1 7.0 10.9 71 (0.40, 0.56) (0.42, 0.55) Example 1-5 A-5 H-1 7.2 15.1 91 (0.42, 0.56) (0.42, 0.56)

It is seen that in Examples 1-1 to 1-5, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 1-1 to 1-5. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 2 Example 2-1

The organic EL device of Example 2-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-1 and A-6 of 93:7 (by mass) from H-1 and A-1 of 95:5 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-6 was obtained.

Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-4

The devices of Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-4 were produced in the same manner as in Example 2-1 except for changing the materials used in Example 2-1 to the materials shown in Table 2. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 2 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-6 H-1 8.1 13.3 100 (0.29, 0.64) (0.32, 0.60) Example 2-1 Comparative B-7 H-1 7.9 13.8 43 (0.25, 0.62) (0.33, 0.58) Example 2-2 Comparative B-8 H-1 8.5 11.8 66 (0.27, 0.61) (0.30, 0.66) Example 2-3 Comparative B-9 H-1 7.8 12.3 83 (0.28, 0.62) (0.33, 0.64) Example 2-4 Example 2-1 A-6 H-1 7.9 14.1 125 (0.28, 0.65) (0.29, 0.64) Example 2-2 A-7 H-1 7.7 14.6 63 (0.24, 0.62) (0.25, 0.60) Example 2-3 A-8 H-1 8.4 12.3 79 (0.26, 0.60) (0.26, 0.62) Comparative A-9 H-1 7.7 12.6 89 (0.28, 0.63) (0.30, 0.64) Example 2-4

It is seen that in Examples 2-1 to 2-4, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 2-1 to 2-4. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 3 Example 3-1

The organic EL device of Example 3-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-2 and A-10 of 93:7 (by mass) from H-1 and A-1 of 95:5 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-10 was obtained.

Examples 3-2 to 3-9 and Comparative Examples 3-1 to 3-8

The devices of Examples 3-2 to 3-9 and Comparative Examples 3-1 to 3-8 were produced in the same manner as in Example 3-1 except for changing the materials used in Example 3-1 to the materials shown in Table 3. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 3 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-10 H-2 8.1 9.2 100 (0.17, 0.32) (0.19, 0.39) Example 3-1 Comparative B-11 H-3 8.8 7.8 43 (0.17, 0.29) (0.21, 0.35) Example 3-2 Comparative B-12 H-3 10.4 3.6 16 (0.17, 0.26) (0.20, 0.35) Example 3-3 Comparative B-13 H-2 7.9 8.7 83 (0.17, 0.28) (0.22, 0.35) Example 3-4 Comparative B-14 H-2 8.3 9.5 71 (0.17, 0.22) (0.21, 0.30) Example 3-5 Comparative C-10 H-2 8.3 8.8 49 (0.17, 0.33) (0.21, 0.41) Example 3-6 Comparative C-36 H-2 8.5 6.8 21 (0.17, 0.29) (0.21, 0.36) Example 3-7 Comparative C-37 H-2 8.6 6.9 22 (0.17, 0.29) (0.21, 0.36) Example 3-8 Example 3-1 A-10 H-2 8.0 9.7 110 (0.18, 0.33) (0.18, 0.36) Example 3-2 A-11 H-3 8.7 8.4 53 (0.18, 0.30) (0.19, 0.32) Example 3-3 A-12 H-3 10.0 4.2 25 (0.18, 0.28) (0.18, 0.30) Example 3-4 A-13 H-2 7.6 9.4 94 (0.17, 0.28) (0.19, 0.31) Example 3-5 A-14 H-2 7.8 9.9 103 (0.17, 0.23) (0.18, 0.25) Example 3-6 A-15 H-2 8.1 9.8 89 (0.17, 0.23) (0.17, 0.24) Example 3-7 A-35 H-2 7.8 9.0 108 (0.17, 0.33) (0.19, 0.35) Example 3-8 A-36 H-2 7.9 7.1 36 (0.17, 0.29) (0.18, 0.31) Example 3-9 A-37 H-2 7.9 7.2 37 (0.17, 0.29) (0.18, 0.31)

It is seen that in Examples 3-1 to 3-6, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 3-1 to 3-5. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low. Furthermore, in Examples 3-6 to 3-9 using A-15, A-35, A-36 and A-37 of the present invention, the device is excellent in terms of durability (the half-luminance time is long), chromaticity shift at device deterioration, and low voltage as compared with Comparative Examples 3-6 to 3-8 using corresponding Compounds C-10, C-36 and C-37 described in JP-A-2008-210941.

Example 4 Example 4-1

The organic EL device of Example 4-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-2 and A-16 of 95:5 (by mass) from H-1 and A-1 of 95:5 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-14 was obtained.

Examples 4-2 to 4-9 and Comparative Examples 4-1 to 4-9

The devices of Examples 4-2 to 4-9 and Comparative Examples 4-1 to 4-9 were produced in the same manner as in Example 4-1 except for changing the materials used in Example 4-1 to the materials shown in Table 4. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 4 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-16 H-2 8.6 9.9 100 (0.29, 0.63) (0.34, 0.63) Example 4-1 Comparative B-17 H-3 9.8 7.9 59 (0.17, 0.29) (0.24, 0.35) Example 4-2 Comparative B-18 H-3 9.4 8.5 57 (0.17, 0.29) (0.23, 0.35) Example 4-3 Comparative B-19 H-2 9.9 7.7 52 (0.20, 0.29) (0.26, 0.35) Example 4-4 Comparative B-20 H-2 8.9 8.2 55 (0.21, 0.30) (0.26, 0.34) Example 4-5 Comparative B-21 H-2 9.0 7.1 44 (0.24, 0.66) (0.29, 0.60) Example 4-6 Comparative B-22 H-2 9.6 7.2 58 (0.23, 0.37) (0.27, 0.42) Example 4-7 Comparative B-23 H-2 9.9 6.8 28 (0.16, 0.24) (0.22, 0.30) Example 4-8 Comparative B-24 H-3 8.9 7.8 46 (0.20, 0.30) (0.26, 0.35) Example 4-9 Example 4-1 A-16 H-2 7.9 11.3 118 (0.29, 0.60) (0.29, 0.61) Example 4-2 A-17 H-3 8.9 8.0 77 (0.16, 0.28) (0.19, 0.31) Example 4-3 A-18 H-3 9.3 9.2 69 (0.18, 0.30) (0.18, 0.32) Example 4-4 A-19 H-2 7.6 9.2 61 (0.21, 0.30) (0.22, 0.31) Example 4-5 A-20 H-2 8.2 9.7 66 (0.22, 0.30) (0.23, 0.33) Example 4-6 A-21 H-2 8.1 9.7 55 (0.24, 0.65) (0.25, 0.63) Example 4-7 A-22 H-2 9.0 8.1 70 (0.23, 0.36) (0.25, 0.38) Example 4-8 A-23 H-2 9.5 7.4 38 (0.16, 0.24) (0.18, 0.26) Example 4-9 A-24 H-3 8.4 8.3 56 (0.19, 0.29) (0.21, 0.32)

It is seen that in Examples 4-1 to 4-9, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 4-1 to 4-9. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 5 Example 5-1

A 0.5 mm-thick 2.5 cm-square glass substrate having thereon ITO film (produced by GEOMATEC Corporation, surface resistance: 10 Ω/sq.) was placed in a cleaning vessel and subjected to ultrasonic cleaning in 2-propanol and then to a UV-ozone treatment for 30 minutes. On this substrate, a solution obtained by diluting poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT/PSS) to 70% with pure water was coated by means of a spin coater to provide a hole transporting layer of 50 nm in thickness, and a methylene chloride solution having dissolved therein H-1 and A-1 in a ratio of 98/2 (by mass) was further coated by means of a spin coater to obtain a light emitting layer of 30 nm in thickness. Thereafter, BAlq [aluminum bis-(2-methyl-8-quinolinato)-4-phenylphenolate] was deposited thereon to a thickness of 40 nm (fourth layer). On this organic compound layer, lithium fluoride of 0.5 nm as a cathode buffer layer and aluminum of 150 nm as a cathode were deposited in a vapor deposition apparatus. The obtained laminate was placed in an argon gas-purged glove box without exposing to the atmosphere and then encapsulated using a stainless steel-made sealing can and an ultraviolet curable adhesive (XNR5516HV, produced by Nagase-Ciba Ltd.) to produce the organic EL device of Example 5-1. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from Compound A-1 of the present invention was obtained.

Examples 5-2 to 5-3 and Comparative Examples 5-1 to 5-3

The devices of Examples 5-2 to 5-3 and Comparative Examples 5-1 to 5-3 were produced in the same manner as in Example 5-1 except for changing the materials used in Example 5-1 to the materials shown in Table 5. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 5 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-1 H-1 11.2 8.3 100 (0.61, 0.38) (0.66, 0.31) Example 5-1 Comparative B-3 H-1 11.8 6.7 66 (0.49, 0.49) (0.53, 0.45) Example 5-2 Comparative B-5 H-1 11.1 9.2 62 (0.41, 0.57) (0.44, 0.52) Example 5-3 Example 5-1 A-1 H-1 10.5 9.0 128 (0.60, 0.37) (0.61, 0.35) Example 5-2 A-3 H-1 10.4 7.8 85 (0.51, 0.49) (0.52, 0.47) Example 5-3 A-5 H-1 10.2 10.4 87 (0.42, 0.56) (0.41, 0.55)

It is seen that in Examples 5-1 to 5-3, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 5-1 to 5-3. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 6 Example 6-1

The organic EL device of Example 6-1 was produced in the same manner as in Example 5-1 except that in Example 5-1, the solution of the third layer (light emitting layer) was coated (film thickness: 50 nm) by changing the compositional ratio to H-1 and A-6 of 96:4 (by mass) from H-1 and A-1 of 98:2 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-6 was obtained.

Example 6-2 and Comparative Examples 6-1 and 6-2

The devices of Example 6-2 and Comparative Examples 6-1 and 6-2 were produced in the same manner as in Example 6-1 except for changing the materials used in Example 6-1 to the materials shown in Table 6. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 6 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-6 H-1 11.6 8.3 100 (0.29, 0.64) (0.33, 0.59) Example 6-1 Comparative B-8 H-1 11.9 6.8 71 (0.27, 0.61) (0.32, 0.68) Example 6-2 Example 6-1 A-6 H-1 10.7 9.0 115 (0.27, 0.65) (0.29, 0.64) Example 6-2 A-8 H-1 11.2 7.5 80 (0.26, 0.60) (0.28, 0.64)

It is seen that in Examples 6-1 and 6-2, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 6-1 and 6-2. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 7 Example 7-1

The organic EL device of Example 7-1 was produced in the same manner as in Example 5-1 except that in Example 5-1, the solution of the third layer (light emitting layer) was coated (film thickness: 50 nm) by changing the compositional ratio to H-4 and A-10 of 96:4 (by mass) from H-1 and A-1 of 98:2 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-6 was obtained.

Example 7-2 and Comparative Examples 7-1 and 7-2

The devices of Example 7-2 and Comparative Examples 7-1 and 7-2 were produced in the same manner as in Example 7-1 except for changing the materials used in Example 7-1 to the materials shown in Table 7. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 7 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-10 H-4 14.1 5.8 100 (0.17, 0.32) (0.20, 0.40) Example 7-1 Comparative B-14 H-4 13.9 6.1 75 (0.17, 0.22) (0.21, 0.30) Example 7-2 Example 7-1 A-10 H-4 13.6 6.7 113 (0.18, 0.33) (0.19, 0.34) Example 7-2 A-14 H-4 13.4 6.9 94 (0.17, 0.22) (0.18, 0.24)

It is seen that in Examples 7-1 and 7-2, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 7-1 and 7-2. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 8 Example 8-1

The organic EL device of Example 8-1 was produced in the same manner as in Example 5-1 except that in Example 5-1, the solution of the third layer (light emitting layer) was coated (film thickness: 50 nm) by changing the compositional ratio to H-4 and A-16 of 96:4 (by mass) from H-1 and A-1 of 98:2 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-16 was obtained.

Examples 8-2 to 8-5 and Comparative Examples 8-1 to 8-5

The devices of Examples 8-2 to 8-5 and Comparative Examples 8-1 to 8-5 were produced in the same manner as in Example 8-1 except for changing the materials used in Example 8-1 to the materials shown in Table 8. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 8 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-15 H-4 13.3 6.1 100 (0.29, 0.63) (0.31, 0.63) Example 8-1 Comparative B-16 H-4 14.5 4.7 64 (0.18, 0.30) (0.20, 0.34) Example 8-2 Comparative B-17 H-4 14.1 5.7 61 (0.18, 0.30) (0.20, 0.33) Example 8-3 Comparative B-20 H-4 13.8 5.3 47 (0.24, 0.66) (0.27, 0.62) Example 8-4 Comparative B-22 H-4 15.5 4.3 32 (0.16, 0.24) (0.23, 0.32) Example 8-5 Example 8-1 A-15 H-4 12.7 6.9 116 (0.29, 0.60) (0.30, 0.62) Example 8-2 A-16 H-4 13.6 5.6 79 (0.17, 0.29) (0.19, 0.32) Example 8-3 A-17 H-4 13.7 6.6 73 (0.19, 0.30) (0.20, 0.32) Example 8-4 A-20 H-4 13.0 6.3 56 (0.24, 0.65) (0.26, 0.64) Example 8-5 A-22 H-4 14.9 5.0 43 (0.16, 0.24) (0.19, 0.27)

It is seen that in Examples 8-1 to 8-5, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Examples 8-1 to 8-5. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 9 Example 9-1

The organic EL device of Example 9-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-1 and A-6 of 93:7 (by mass) from H-1 and A-1 of 98:2 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-6 was obtained.

Examples 9-2 to 9-6 and Comparative Example 9-1

The devices of Examples 9-2 to 9-6 and Comparative Example 9-1 were produced in the same manner as in Example 9-1 except for changing the materials used in Example 9-1 to the materials shown in Table 9. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 9 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-6 H-1 8.1 13.3 100 (0.29, 0.64) (0.32, 0.60) Example 9-1 Example 9-1 A-6 H-1 7.9 14.1 125 (0.28, 0.65) (0.29, 0.64) Example 9-2 A-25 H-1 7.8 14.0 121 (0.29, 0.64) (0.30, 0.63) Example 9-3 A-26 H-1 7.7 13.8 109 (0.29, 0.64) (0.31, 0.62) Example 9-4 A-27 H-1 8.0 13.8 119 (0.30, 0.62) (0.31, 0.63) Example 9-5 A-28 H-1 7.9 14.0 121 (0.31, 0.63) (0.31, 0.62) Example 9-6 A-29 H-1 7.9 13.9 119 (0.29, 0.64) (0.30, 0.63)

It is seen that in Examples 9-1 to 9-6, the compound of the present invention is used as the light emitting material and therefore, although the degree of effect differs according to the number of partial structures and the substitution position, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Example 9-1. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 10 Example 10-1

The organic EL device of Example 10-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-2 and A-14 of 90:10 (by mass) from H-1 and A-1 of 95:5 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-14 was obtained.

Examples 10-2 to 10-4 and Comparative Example 10-1

The devices of Examples 10-2 to 10-4 and Comparative Example 10-1 were produced in the same manner as in Example 10-1 except for changing the materials used in Example 10-1 to the materials shown in Table 10. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 10 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-14 H-2 8.3 9.5 100 (0.17, 0.22) (0.21, 0.30) Example 10-1 Example 10-1 A-14 H-2 7.8 10.2 143 (0.17, 0.23) (0.18, 0.24) Example 10-2 A-30 H-2 7.9 10.1 145 (0.17, 0.22) (0.17, 0.23) Example 10-3 A-31 H-2 8.1 9.7 127 (0.17, 0.23) (0.19, 0.26) Example 10-4 A-32 H-2 8.1 9.7 125 (0.17, 0.23) (0.19, 0.26)

It is seen that in Examples 10-1 to 10-4, the compound of the present invention is used as the light emitting material and therefore, although the degree of effect differs according to the number of partial structures and the substitution position, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Example 10-1. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 11 Example 11-1

The organic EL device of Example 11-1 was produced in the same manner as in Example 1-1 except that in Example 1-1, the film of the third layer (light emitting layer) was deposited (film thickness: 50 nm) by changing the compositional ratio to H-2 and A-17 of 90:10 (by mass) from H-1 and A-1 of 95:5 (by mass). A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from A-17 was obtained.

Examples 11-2 and 11-3 and Comparative Example 11-1

The devices of Examples 11-2 and 11-3 and Comparative Example 11-1 were produced in the same manner as in Example 11-1 except for changing the materials used in Example 11-1 to the materials shown in Table 11. A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from respective light emitting materials was obtained.

TABLE 11 External Half- Chromaticity Light Emitting Layer Drive Quantum Luminance after Light Voltage at Efficiency Time at Decrease to Emitting Host 100 cd/m² at 100 1000 cd/m² Initial Half Material Material (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative B-17 H-3 9.8 7.9 100 (0.17, 0.29) (0.24, 0.35) Example 11-1 Example 11-1 A-17 H-3 8.8 8.6 126 (0.16, 0.28) (0.20, 0.33) Example 11-2 A-33 H-3 9.0 8.5 121 (0.16, 0.28) (0.20, 0.32) Example 11-3 A-34 H-3 8.9 8.6 125 (0.16, 0.29) (0.20, 0.32)

It is seen that in Examples 11-1 to 11-3, the compound of the present invention is used as the light emitting material and therefore, the device exhibits high efficiency and a long half-luminance time and is excellent in terms of durability as compared with Comparative Example 11-1. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Example 12 Example 12-1

A 100 μm-thick 2.5 cm-square glass substrate having thereon indium tin oxide (ITO) film (produced by GEOMATEC Corporation, surface resistance: 10 Ω/sq.) was placed in a cleaning vessel and subjected to ultrasonic cleaning in 2-propanol and then to a UV-ozone treatment for 30 minutes. On this transparent anode (ITO film), the following organic compound layers were sequentially deposited by the vacuum deposition method.

-   First layer: CuPc (copper phthalocyanine), thickness: 120 nm -   Second layer: NPD (N,N′-di-α-naphthyl-N,N′-diphenyl)-benzidine,     thickness: 7 nm -   Third layer: CBP (4,4′-di(9-carbazoyl)biphenyl), thickness: 3 nm -   Fourth layer (light emitting layer): dopant (9 mass %), mCBP (91     mass %), thickness: 30 nm -   Fifth layer: first electron transporting material (Balq), thickness:     30 nm

On this layer, lithium fluoride of 1 nm and metal aluminum of 100 nm were deposited in this order to form a cathode.

The obtained laminate was placed in an argon gas-purged glove box without exposing to the atmosphere and then encapsulated using a stainless steel-made sealing can and an ultraviolet curable adhesive (XNR5516HV, produced by Nagase-Ciba Ltd.) to obtain the organic EL device of Example 12-1.

Examples 12-2 to 12-16 and Comparative Examples 12-1 to 12-13

The devices of Examples 12-2 to 12-16 and Comparative Examples 12-1 to 12-13 were produced in the same manner as in Example 12-1 except for changing the light emitting material of the device as shown in Table 12 below.

(Performance Evaluation of Organic Electroluminescence Device)

A DC voltage was applied to the organic EL device to produce luminescence by using Source Measure Unit Model 2400 manufactured by Toyo Corp., as a result, luminescence derived from the light emitting material used was obtained. The results are shown together in Table 12.

TABLE 12 External Half- Chromaticity Drive Quantum Luminance after Light Voltage Efficiency Time at Decrease to Emitting at 100 at 100 1000 cd/m² Initial Half Material cd/m² (V) cd/m² (%) (relative value) Chromaticity Luminance Comparative ref 1 9.2 3.1 100 (0.17, 0.29) (0.23, 0.37) Example 12-1 Example 12-1 I-1 9.0 5.1 115 (0.17, 0.28) (0.20, 0.35) Comparative ref 2 9.3 8.8 85 (0.17, 0.29) (0.23, 0.37) Example 12-2 Comparative ref 3 9.6 7.0 120 (0.17, 0.28) (0.21, 0.36) Example 12-3 Example 12-2 I-2 9.2 9.9 135 (0.17, 0.28) (0.19, 0.32) Example 12-3 I-3 9.3 9.8 125 (0.17, 0.30) (0.20, 0.33) Comparative ref 4 9.5 6.6 128 (0.17, 0.29) (0.22, 0.35) Example 12-4 Example 12-4 I-4 9.2 7.2 143 (0.17, 0.29) (0.20, 0.32) Comparative ref 5 9.5 7.0 122 (0.17, 0.30) (0.23, 0.34) Example 12-5 Example 12-5 I-5 9.0 7.8 139 (0.17, 0.29) (0.20, 0.32) Example 12-6 I-6 9.0 7.7 138 (0.17, 0.29) (0.20, 0.33) Example 12-7 I-7 9.2 7.6 135 (0.17, 0.30) (0.19, 0.32) Example 12-8 I-8 9.2 7.6 137 (0.17, 0.30) (0.19, 0.31) Comparative ref 6 9.0 8.0 88 (0.17, 0.30) (0.23, 0.39) Example 12-6 Example 12-9 I-9 8.8 8.8 105 (0.18, 0.31) (0.22, 0.36) Comparative ref 7 9.3 6.1 95 (0.21, 0.34) (0.26, 0.39) Example 12-7 Example 12-10 I-10 9.0 6.7 107 (0.21, 0.33) (0.25, 0.35) Comparative ref 8 9.4 6.0 92 (0.24, 0.36) (0.28, 0.42) Example 12-8 Example 12-11 I-11 9.2 6.9 106 (0.23, 0.35) (0.26, 0.39) Comparative ref 9 9.5 5.8 60 (0.26, 0.54) (0.29, 0.59) Example 12-9 Example 12-12 I-12 9.3 6.5 70 (0.26, 0.54) (0.27, 0.56) Comparative ref 10 9.3 6.1 130 (0.19, 0.28) (0.24, 0.33) Example 12-10 Example 12-13 I-13 9.1 6.7 142 (0.19, 0.28) (0.21, 0.30) Comparative ref 11 9.2 6.7 135 (0.19, 0.28) (0.25, 0.32) Example 12-11 Example 12-14 I-14 9.0 7.5 147 (0.18, 0.28) (0.20, 0.31) Comparative ref 12 9.5 6.6 75 (0.21, 0.34) (0.25, 0.38) Example 12-12 Example 12-15 I-15 9.2 7.3 88 (0.20, 0.34) (0.23, 0.36) Comparative ref-13 9.2 7.0 90 (0.17, 0.30) (0.24, 0.36) Example 12-13 Example 12-16 I-16 9.0 7.8 105 (0.17, 0.29) (0.20, 0.32)

It is seen that in Examples 12-1 to 12-16, the compound of the present invention is used as the light emitting material and therefore, both high efficiency and a long half-luminance time are satisfied and the device is excellent in terms of durability as compared with Comparative Examples 12-1 to 12-13 using corresponding compounds described in U.S. Patent Application Publication 2008-297033. Also, the chromaticity shift is less caused at the device deterioration and the voltage is low.

Industrial Applicability

According to the present invention, an organic electroluminescence device having high luminous efficiency (for example, external quantum efficiency), high durability and a long life of the device and causing little chromaticity shift after device deterioration can be provided.

This application is based on Japanese patent application No. 2009-201150 filed on Aug. 31, 2009, the entire content of which is hereby incorporated by reference, the same as if set forth at length.

Reference Signs List

-   2 Substrate -   3 Anode -   4 Hole injection layer -   5 Hole transporting layer -   6 Light emitting layer -   7 Hole blocking layer -   8 Electron transporting layer -   9 Cathode -   10 Organic electroluminescence device (organic EL device) -   11 Organic layer -   12 Protective layer -   14 Adhesive layer -   16 Sealing container -   20 Light emission apparatus -   30 Light scattering member -   30A Light incident surface -   30B Light output surface -   32 Fine particle -   40 Illumination apparatus 

The invention claimed is:
 1. An organic electroluminescence device comprising, on a substrate: a pair of electrodes; and at least one organic layer between the electrodes, the organic layer containing a light emitting layer, wherein the light emitting layer contains as a light emitting material a metal complex represented by formula (2) having a group represented by the following formula (I), a metal complex represented by formula (14) having the group represented by the following formula (I), or a metal complex represented by formula (A9) having the group represented by the following formula (I):

wherein R₁ represents an alkyl group; R₂ and R₃ each independently represent a hydrogen atom or an alkyl group; n_(s) represents an integer of 1 to 6; and Z represents a saturated 5- to 8-membered ring:

wherein M²¹ represents Ir; A²¹ to A²³ each independently represent a nitrogen atom or a carbon atom; Z²¹ represents a quinoline ring, an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, and a cyano group; Z²² represents a benzene ring, a pyrazole ring, a pyridine ring, a benzoxazole ring, or a thiophene ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, and a cyano group; L²² and L²³ each represent a carbon atom, a nitrogen atom, or an oxygen atom and form together with E²¹ a bidentate ligand of a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S²¹ and S²² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S²¹s or S²²s may be the same as or different from every other S²¹ or S²², respectively:

wherein A¹⁴¹ to A¹⁴⁶ each independently represent a nitrogen atom or a carbon atom; Z¹⁴¹ and 2 ¹⁴² each independently represent an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring; Z¹⁴³ and Z¹⁴⁴ each independently represent an isoquinoline ring, a benzoxazole ring, a benzene ring, a pyridine ring, an imidazole ring, or a pyrazole ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, and a cyano group; E¹⁴¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁴¹ to S¹⁴⁴ each independently represent the group represented by formula (I); n, m, k and l represents an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁴¹s, S¹⁴²s, S¹⁴³S S¹⁴⁴s may be the same as or different from every other S¹⁴¹,S¹⁴², S¹⁴³ or S¹⁴⁴, respectively:

wherein R_(ia) to R_(li) each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a cyano group and at least one of R_(1a) to R_(1i) represents the group represented by formula (I); X—Y represents a monoanionic bidentate ligand selected from at least one of a diketone and a picolinic acid derivative; and n represents an integer of 1 to
 3. 2. The organic electroluminescence device according to claim 1, wherein n_(s) in formula (I) represents an integer of
 1. 3. The organic electroluminescence device according to claim 1, wherein R₂ and R₃ in formula (I) each represent a hydrogen atom.
 4. The organic electroluminescence device according to claim 1, wherein Z in formula (I) represents a cyclopentane ring or a cyclohexyl ring.
 5. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (2) is represented by the following formula (3):

wherein M³¹ represents Ir; A³¹ and A³² each independently represent a nitrogen atom or a carbon atom; R³³ to R³⁶ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; Z³² represents a benzene ring, a pyrazole ring, a pyridine ring, a benzoxazole ring, or a thiophene ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, or a cyano group; L³² and L³³ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom; E³¹ represents a phenylpyridinc, a pyridylpyridinc, a picolinic acid, or an acetylacetone together with L³² and L³³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S³¹ and S³² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S³¹s or S³²s may be the same as or different from every other S³¹ or S³², respectively.
 6. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (2) is represented by the following formula (4):

wherein M⁴¹ represents Ir; R⁴³ to R⁴⁶ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; B⁴¹ to B⁴⁴ each independently represent a nitrogen atom or C—R⁴⁷, a number of the nitrogen atoms of B⁴¹ to B⁴⁴ is 0 or 1, and R⁴⁷ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R⁴⁷s may be the same as or different from every other R^(47;) L⁴² and L⁴³ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom; E⁴¹ represents a phenylpyridine, pyridylpyridine, picolinic acid, or an acetylacetone together with L⁴² and L⁴³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S⁴¹ and S⁴² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S⁴¹s or S⁴²s may be the same as or different from every other S⁴¹ or S⁴², respectively.
 7. The organic electroluminescence device according to claim 6, wherein the metal complex represented by formula (4) is represented by the following formula (6-1):

wherein M⁶¹¹ represents Ir; R⁶¹³ to R⁶¹⁹ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; L⁶¹² and L⁶¹³ each represent a carbon atom, a nitrogen atom, or an oxygen atom; E⁶¹¹ represents a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone together with L⁶¹² and L⁶¹³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S⁶¹¹ and S⁶¹² each independently represent the group represented by formula (I); n represents an integer of 0 to 4; m represents an integer of 0 to 3; n+m is an integer of 1 to 4; and S⁶¹¹s or S⁶¹²s may be the same as or different from every other S⁶¹¹ or S⁶¹², respectively.
 8. The organic electroluminescence device according to claim 6, wherein the metal complex represented by formula (4) is represented by the following formula (5):

wherein M⁵¹ represents Ir; R⁵³ to R⁵⁹ and R⁵¹⁰ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; L⁵² and L⁵³ each represent a carbon atom, a nitrogen atom, or an oxygen atom; E⁵¹ represents a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone together with L⁵² and L⁵³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S⁵¹ and S⁵² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S⁵¹s or S⁵²s may be the same as or different from every other S⁵¹ or S⁵², respectively.
 9. The organic electroluminescence device according to claim 8, wherein the metal complex represented by formula (5) is represented by the following formula (5-1)

wherein M⁵¹¹ represents Ir; R⁵¹³ to R⁵¹¹⁰ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R⁵¹¹¹ to R⁵¹¹⁴ represent a hydrogen atom; S⁵¹¹ and S⁵¹² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S⁵¹¹s or S⁵¹²s may be the same as or different from every other S⁵¹¹ or S⁵¹², respectively.
 10. The organic electroluminescence device according to claim 8, wherein the metal complex represented by formula (5) is represented by the following formula (5-2):

wherein M⁵²¹ represents Ir; R⁵²³ to R⁵²¹⁰ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R⁵²¹¹ and R⁵²¹³ represent a methyl group; R⁵²¹² represents a hydrogen atom; S⁵²¹ and S⁵²² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S⁵²¹s or S⁵²²s may be the same as or different from every other S⁵²¹ or S⁵²², respectively.
 11. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (2) is represented by the following formula (7-1):

wherein M⁷¹¹ represents Ir; R⁷¹³ to ⁷¹⁸ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; L⁷¹² and L⁷¹³ each represent a carbon atom, a nitrogen atom, or an oxygen atom; E⁷¹¹ represents a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone together with L⁷¹² and L⁷¹³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S⁷¹¹ and S⁷¹² each independently represent the group represented by formula (I); n represents an integer of 0 to 4; m represents an integer of 0 to 2; n+m is an integer of 1 to 4; and S⁷¹¹s or S⁷¹²s may be the same as or different from every other S⁷¹¹ or S⁷¹², respectively.
 12. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (2) is represented by the following formula (9):

wherein M⁹¹ represents Ir; R⁹³ and R⁹⁴ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R⁹⁵ represents a hydrogen atom or an alkyl group; B⁹¹ to B⁹⁴ each independently represent a nitrogen atom or C—R⁹⁶, a number of the nitrogen atoms of B⁹¹ to B⁹⁴ is 0 or 1, R⁹⁶ represents a hydrogen atom, an alkyl group, a fluorine atom, a methoxy group, an aryl group, or a cyano group, and R⁹⁶s may be the same as or different from every other R⁹⁶; L⁹² and L⁹³ each represent a carbon atom, a nitrogen atom, or an oxygen atom; E⁹¹ represents a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone together with L⁹² and L⁹³, respectively; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S⁹¹ and S⁹² each independently represent the group represented by formula (I); n represents an integer of 0 to 3; m represents an integer of 0 to 4; n+m is an integer of 1 to 4; and S⁹¹s or S⁹²s may be the same as or different from every other S⁹¹ or S⁹², respectively.
 13. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (2) is represented by the following formula (12):

wherein M¹²¹ represents Ir; R¹²³ to R¹²⁵ independently represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; B¹²¹ to B¹²⁴ each independently represent a nitrogen atom or C—R¹²⁶, a number of the nitrogen atoms in B¹²¹ to B¹²⁴ is 0 or 1, R¹²⁶ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group, R¹²⁶s may be the same as or different from every other R¹²⁶; L¹²² and L¹²³ each represent a carbon atom, a nitrogen atom, or an oxygen atom; E¹²¹ represents a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone together with L¹²² and L¹²³; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S¹²¹ and S¹²² each independently represent the group represented by formula (I); n represents an integer of 0 to 3; m represents an integer of 0 to 4; n+m is an integer of 1 to 4; and S¹²¹s or S¹²²s may be the same as or different from every other S¹²¹ or S¹²², respectively.
 14. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (14) is represented by the following formula (15):

wherein A¹⁵¹ to A¹⁵⁴ each independently represent a nitrogen atom or a carbon atom; R¹⁵³ to R¹⁵⁸ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; Z¹⁵¹ and Z¹⁵² each independently represent a benzene ring, an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring; E¹⁵¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁵¹ to S¹⁵⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁵¹s, S¹⁵²s, S¹⁵³s or S¹⁵⁴s may be the same as or different from every other S¹⁵¹, S¹⁵², S¹⁵³ or ¹⁵⁴, respectively.
 15. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (14) is represented by the following formula (16):

wherein R¹⁶³ to R¹⁶⁸ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; B¹⁶¹ to B¹⁶⁸ each independently represent a nitrogen atom or C—R¹⁶⁹, a number of the nitrogen atoms of B¹⁶¹ to B¹⁶⁴ is 0 or 1, a number of the nitrogen atoms of B¹⁶⁵ to B¹⁶⁸ is 0 or 1, R¹⁶⁹ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group, and R¹⁶⁹s may be the same as or different from every other R¹⁶⁹; E¹⁶¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represents an alkyl group; S¹⁶¹ to S¹⁶⁴ each independently represent the group represented by formula (I); n, m, k and l represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁶¹s, S¹⁶²s, S¹⁶³or S¹⁶⁴ may be the same as or different from every other S¹⁶¹, S¹⁶², S¹⁶³ or S¹⁶⁴, respectively.
 16. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (14) is represented by the following formula (17):

wherein R¹⁷³ to R¹⁷⁸ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; A¹⁷¹ to A¹⁷⁴ each independently represent a nitrogen atom or a carbon atom; D¹⁷¹ to D¹⁷⁶ each independently represent an atom selected from a carbon atom and a nitrogen atom; 5-membered rings formed by D¹⁷¹ to D¹⁷³, A¹⁷¹ and A¹⁷² and by D¹⁷⁴ to D¹⁷⁶, A¹⁷³ and A¹⁷⁴ represent a pyrazole ring; when D¹⁷¹ to D¹⁷⁶ can be further substituted, D¹⁷¹ to D¹⁷⁶ may have an alkyl group, a fluorine atom, or a cyano group as a substituent; E¹⁷¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁷¹ to S¹⁷⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁷¹s, S¹⁷²s, S¹⁷³s, or S¹⁷⁴s may be the same as or different from every other S¹⁷¹, S¹⁷², S¹⁷³ or S¹⁷⁴, respectively.
 17. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (14) is represented by the following formula (18):

wherein A¹⁸¹ to A¹⁸⁶ each independently represent a nitrogen atom or a carbon atom; D¹⁸¹ to D¹⁸⁴ each independently represent an atom selected from a carbon atom and a nitrogen atom; each of 5-membered rings defined by D¹⁸¹, D¹⁸², A¹⁸¹, a nitrogen atom and a carbon atom or by D¹⁸³, D¹⁸⁴, A¹⁸⁴, a nitrogen atom and a carbon atom has two nitrogen atoms; bonds between the atoms in the 5-membered rings defined by D¹⁸¹, D¹⁸², A¹⁸¹, a nitrogen atom and a carbon atom and by D¹⁸³, D¹⁸⁴, A¹⁸⁴, a nitrogen atom and a carbon atom are a single bond or a double bond; when D¹⁸¹ to D¹⁸⁴ can be further substituted, D¹⁸¹ to D¹⁸⁴ may have an alkyl group, a fluorine atom, or a cyano group as a substituent; Z¹⁸¹ and Z¹⁸² each independently represent a benzene ring, an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring; E¹⁸¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁸¹ to S¹⁸⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁸¹s,S¹⁸²s, S¹⁸³s or S¹⁸⁴s may be the same as or different from every other S¹⁸¹,S¹⁸² , S¹⁸³, or S¹⁸⁴, respectively.
 18. The organic electroluminescence device according to claim 1, wherein the metal complex represented by formula (14) is represented by the following formula (19):

wherein A¹⁹¹ and A¹⁹² each independently represent a nitrogen atom or a carbon atom; D¹⁹¹ to D¹⁹⁴ each independently represent an atom selected from a carbon atom and a nitrogen atom; each of 5-membered rings defined by D¹⁹¹, D¹⁹², A¹⁹¹,a nitrogen atom and a carbon atom or by D¹⁹³, D¹⁹⁴, A¹⁹², a nitrogen atom and a carbon atom has two nitrogen atoms; bonds between the atoms in the 5-membered rings formed by D¹⁹¹, D¹⁹², A¹⁹¹, a nitrogen atom and a carbon atom or by D¹⁹³, D¹⁹⁴, A¹⁹², a nitrogen atom and a carbon atom are a single bond or a double bond; when D¹⁹¹ to D¹⁹⁴ can be further substituted, D¹⁹¹ to D¹⁹⁴ may have an alkyl group, a fluorine atom, or a cyano group as a substituent; B¹⁹¹ to B¹⁹⁸ each independently represent a nitrogen atom or C—R¹⁹⁹, a number of the nitrogen atoms in B¹⁹¹ to B¹⁹⁴ is 0 or 1, a number of the nitrogen atoms in B¹⁹⁵ to B¹⁹⁸ is 0 or 1, R¹⁹⁹ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R¹⁹⁹s may be the same as or different from every other R¹⁹⁹; E¹⁹¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁹¹ to S¹⁹⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁹¹s, S¹⁹²s, S^(l93)s or S¹⁹⁴s may be the same as or different from every other S¹⁹¹, S¹⁹², S¹⁹³ or S¹⁹⁴, respectively.
 19. The organic electroluminescence device according to claim 18, wherein the metal complex represented by formula (19) is represented by the following formula (20):

wherein R²⁰³ to R²⁰⁶ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; B²⁰¹ to B²⁰⁸ each independently represent a nitrogen atom or C—R²⁰⁷, a number of the nitrogen atoms in B²⁰¹to B²⁰⁴ is 0 or 1, a number of the nitrogen atoms in B²⁰⁵ to B²⁰⁸ is 0 or 1, R²⁰⁷ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group, R²⁰⁷s may be the same as or different from every other R²⁰⁷; E²⁰¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S²⁰¹ to S²⁰⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 or 2; and S²⁰¹s, S²⁰²s, S²⁰³s or S²⁰⁴s may be the same as or different from every other S²⁰¹, S²⁰², S²⁰³ or S²⁰⁴, respectively.
 20. The organic electroluminescence device according to claim 18, wherein the metal complex represented by formula (19) is represented by the following formula (21):

wherein R²¹³ and R²¹⁴ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; R²¹⁵ and R²¹⁶ each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group; B²¹¹ to B²¹⁸ each independently represent a nitrogen atom or C—R²¹⁷, a number of the nitrogen atoms of B²¹¹ to B²¹⁴ is 0 or 1, a number of the nitrogen atoms of B²¹⁵ to B²¹⁸ is 0 or 1, R²¹⁷ represents a hydrogen atom, an alkyl group, a fluorine atom, or a cyano group, R²¹⁷s may be the same as or different from every other R²¹⁷; E²¹¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S²¹¹ to S²¹⁴ each independently represent the group represented by formula (I); n, m, k and l each represent an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S²¹¹s, S^(2l2)s, S²¹³s or S²¹⁴s may be the same as or different from every other S²¹¹, S²¹², S²¹³, or S²¹⁴.
 21. The organic electroluminescence device according to claim 1, wherein the group represented by formula (I) in the metal complex in formula (A9) is represented by the following a2, a5, a9 or a12:


22. The organic electroluminescence device according to claim 1, wherein a carbazole or indole structure-containing material is further contained in any one of the at least one organic layer.
 23. The organic electroluminescence device according to claim 1, wherein a carbazole or indole structure-containing material is further contained in the light emitting layer.
 24. A composition comprising a metal complex represented by formula (2) having a group represented by formula (I), a metal complex represented by formula (14) having the group represented by formula (I), or a metal complex represented by formula (A9) having the group represented by formula (I):

wherein R₁ represents an alkyl group; R₂ and R₃ each independently represent a hydrogen atom or an alkyl group; n_(s) represents an integer of 1; and Z represents a saturated 5- to 8-membered ring;

wherein M²¹ represents Ir; A²¹ to A²³ each independently represent a nitrogen atom or a carbon atom; Z²¹ represents a quinoline ring, an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, and a cyano group; Z²² represents a benzene ring, a pyrazole ring, a pyridine ring, a benzoxazole ring, or a thiophene ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, and a cyano group; L²² and L²³ each represent a carbon atom, a nitrogen atom, or an oxygen atom and form together with E²¹ a bidentate ligand of a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S²¹ and S²² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and S²¹s or S²²s may be the same as or different from every other S²¹ or S²², respectively:

wherein A¹⁴¹ to A¹⁴⁶ each independently represent a nitrogen atom or a carbon atom; Z¹⁴¹ and Z¹⁴² each independently represent an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring; Z¹⁴³ and Z¹⁴⁴ each independently represent an isoquinoline ring, a benzoxazole ring, a benzene ring, a pyridine ring, an imidazole ring, or a pyrazole ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, and a cyano group; E¹⁴¹ represents a divalent linking group represented by —C(R¹)(R²)—, wherein R¹ and R² represent an alkyl group; S¹⁴¹ to S¹⁴⁴ each independently represent the group represented by formula (I); n, m, k and l represents an integer of 0 to 2; n+m+k+l is an integer of 1 to 2; and S¹⁴¹s, S¹⁴²s, S¹⁴³s or S¹⁴⁴s may be the same as or different from every other S¹⁴¹, S¹⁴²,S¹⁴³ or S¹⁴⁴, respectively:

wherein R_(1a) to R_(1i), each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a cyano group and at least one of R_(1a) to R_(1i)represents the group represented by formula (I); X—Y represents a monoanionic bidentate ligand selected from at least one of a diketone and a picolinic acid derivative; and n represents an integer of 1 to
 3. 25. A light emitting layer comprising the composition of claim
 24. 26. A light emission apparatus comprising the organic electroluminescence device according to claim
 1. 27. A display apparatus comprising the organic electroluminescence device according to claim
 1. 28. An illumination apparatus comprising the organic electroluminescence device according to claim
 1. 29. A composition comprising a metal complex represented by formula (2) and having a group represented by formula (I):

wherein M²¹ represents Ir; A²¹ to A²³ each independently represent a nitrogen atom or a carbon atom; Z²¹ represents a quinoline ring, an isoquinoline ring, a benzoxazole ring, a pyridine ring, an imidazole ring, or a pyrazole ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, or a cyano group; Z²² represents a benzene ring, a pyrazole ring, a pyridine ring, a benzoxazole ring, or a thiophene ring, and these rings may have a substituent selected from the group consisting of an alkyl group, a fluorine atom, a methoxy group, an aryl group, or a cyano group; L²² and L²³ each represent a carbon atom, a nitrogen atom, or an oxygen atom and form together with E²¹ a bidentate ligand of a phenylpyridine, a pyridylpyridine, a picolinic acid, or an acetylacetone; k represents an integer of 1 to 3; l represents an integer of 0 to 2; k+l is 3; S²¹ and S²² each independently represent the group represented by formula (I); n and m each represent an integer of 0 to 4; n+m is an integer of 1 to 4; and wherein S²¹s or S²²s may be the same as or different from every other S²¹ or S²², respectively:

wherein R₁ represents an alkyl group; R₂ and R₃ each independently represent a hydrogen atom or an alkyl group; n_(s) represents an integer of 1; and Z represents a saturated 5- to 8-membered ring. 